Prion urine comprises a glycosaminoglycan-light chain IgG complex that can be stained by Congo red

A Study of Role of Urinary Congophilia in Early Detection of Preeclampsia

Introduction Preeclampsia and eclampsia are important causes of maternal morbidity. Preeclapmtic women secrete misfolded proteins in the urine. Buhimschi et al had developed a new test for diagnosis of preeclampsia. This test is based on staining of misfolded protein with Congo red dye. Misfolded proteins are derived from syncytiotrophoblast microparticles (STBMs). These STBM are membrane bound vesicles and contain misfolded proteins. In preeclampsia, glomeruli of kidneys are disrupted and these damaged protein reach the urine.

Aim and Objective This study aimed to investigate the role of urinary congophilia in early prediction of preeclampsia.

Materials and Methods This test was done in 250 pregnant women attending the Gynaecological Outpatient Department. Urine sample of early morning was taken and test was done in the Department of Biochemistry. The included pregnant women were of gestational age between 14 and 18 weeks. The staining of urine with Congo red dye was done and washed with methanol. The retention of dye was interpreted with naked eye. The more retention of dye, the more chances of developing preeclampsia later. The patients were followed-up till delivery. The patents who developed preeclampsia later part of pregnancy were recorded. Mean arterial pressure (MAP) and past history and body mass index were also recorded.

Results Out of 250 patients, 30 developed preeclampsia later. A total of 34 patients were having positive urinary congophilia and only 20 patients developed preeclampsia later. MAP more than 90 mm Hg is abnormal but 66.7% of patients who developed preeclampsia had MAP >90 mm Hg. In 16.7% of patients, who developed preeclampsia later, had positive past history of hypertension. In 66.7% of patients, who were positive for urinary congophilia, later developed preeclampsia.

Conclusion Preeclampsia and eclampsia are important causes of maternal mortality and morbidity. So, early detection can prevent complications and timely management. Urinary congophilia is one of such test which can help in early prediction of preeclampsia. If it is combined with past maternal history and MAP, it gives more good results. The detection rate is much higher if signs and symptoms of preeclampsia are noticed timely.

Protein Misfolding during Pregnancy: New Approaches to Preeclampsia Diagnostics

Preeclampsia (PE) is a multisystem heterogeneous complication of pregnancy remaining a leading cause of maternal and perinatal morbidity and mortality over the world. PE has a large spectrum of clinical features and symptoms, which make diagnosis challenging. Despite a long period of studying, PE etiology is still unclear and there are no reliable rapid tests for early diagnosis of this disease. During the last decade, it was shown that proteins misfolding and aggregation are associated with PE. Several proteins, including amyloid beta peptide, transthyretin, alpha-1 antitrypsin, albumin, IgG k-free light chains, and ceruloplasmin are dysregulated in PE, resulting in toxic deposition of amyloid-like aggregates in the placenta and body fluids. It is also possible that aggregated proteins induce defective trophoblast invasion, placental ischemia, ER stress, and promote PE manifestation. The fact that protein aggregation is an emerging biomarker of PE provides an opportunity to develop new diagnostic approaches based on amyloids special features, such as Congo red (CR) staining and thioflavin T (ThT) enhanced fluorescence.

Protein misfolding, congophilia, oligomerization, and defective amyloid processing in preeclampsia

Preeclampsia is a pregnancy-specific disorder of unknown etiology and a leading contributor to maternal and perinatal morbidity and mortality worldwide. Because there is no cure other than delivery, preeclampsia is the leading cause of iatrogenic preterm birth. We show that preeclampsia shares pathophysiologic features with recognized protein misfolding disorders. These features include urine congophilia (affinity for the amyloidophilic dye Congo red), affinity for conformational state–dependent antibodies, and dysregulation of prototype proteolytic enzymes involved in amyloid precursor protein (APP) processing. Assessment of global protein misfolding load in pregnancy based on urine congophilia (Congo red dot test) carries diagnostic and prognostic potential for preeclampsia. We used conformational state–dependent antibodies to demonstrate the presence of generic supramolecular assemblies (prefibrillar oligomers and annular protofibrils), which vary in quantitative and qualitative representation with preeclampsia severity. In the first attempt to characterize the preeclampsia misfoldome, we report that the urine congophilic material includes proteoforms of ceruloplasmin, immunoglobulin free light chains, SERPINA1, albumin, interferon-inducible protein 6-16, and Alzheimer’s β-amyloid. The human placenta abundantly expresses APP along with prototype APP-processing enzymes, of which the α-secretase ADAM10, the β-secretases BACE1 and BACE2, and the γ-secretase presenilin-1 were all up-regulated in preeclampsia. The presence of β-amyloid aggregates in placentas of women with preeclampsia and fetal growth restriction further supports the notion that this condition should join the growing list of protein conformational disorders. If these aggregates play a pathophysiologic role, our findings may lead to treatment for preeclampsia.

Prion disease detection, PMCA kinetics, and IgG in urine from sheep naturally/experimentally infected with scrapie and deer with preclinical/clinical chronic wasting disease

Prion diseases, also known as transmissible spongiform encephalopathies, are fatal neurodegenerative disorders. Low levels of infectious agent and limited, infrequent success of disease transmissibility and PrP(Sc) detection have been reported with urine from experimentally infected clinical cervids and rodents. We report the detection of prion disease-associated seeding activity (PASA) in urine from naturally and orally infected sheep with clinical scrapie agent and orally infected preclinical and infected white-tailed deer with clinical chronic wasting disease (CWD). This is the first report on PASA detection of PrP(Sc) from the urine of naturally or preclinical prion-diseased ovine or cervids. Detection was achieved by using the surround optical fiber immunoassay (SOFIA) to measure the products of limited serial protein misfolding cyclic amplification (sPMCA). Conversion of PrP(C) to PrP(Sc) was not influenced by the presence of poly(A) during sPMCA or by the homogeneity of the PrP genotypes between the PrP(C) source and urine donor animals. Analysis of the sPMCA-SOFIA data resembled a linear, rather than an exponential, course. Compared to uninfected animals, there was a 2- to 4-log increase of proteinase K-sensitive, light chain immunoglobulin G (IgG) fragments in scrapie-infected sheep but not in infected CWD-infected deer. The higher-than-normal range of IgG levels found in the naturally and experimentally infected clinical scrapie-infected sheep were independent of their genotypes. Although analysis of urine samples throughout the course of infection would be necessary to determine the usefulness of altered IgG levels as a disease biomarker, detection of PrP(Sc) from PASA in urine points to its potential value for antemortem diagnosis of prion diseases.

Urinary alpha1-antichymotrypsin: a biomarker of prion infection

The occurrence of blood-borne prion transmission incidents calls for identification of potential prion carriers. However, current methods for intravital diagnosis of prion disease rely on invasive tissue biopsies and are unsuitable for large-scale screening. Sensitive biomarkers may help meeting this need. Here we scanned the genome for transcripts elevated upon prion infection and encoding secreted proteins. We found that alpha(1)-antichymotrypsin (alpha(1)-ACT) was highly upregulated in brains of scrapie-infected mice. Furthermore, alpha(1)-ACT levels were dramatically increased in urine of patients suffering from sporadic Creutzfeldt-Jakob disease, and increased progressively throughout the disease. Increased alpha(1)-ACT excretion was also found in cases of natural prion disease of animals. Therefore measurement of urinary alpha(1)-ACT levels may be useful for monitoring the efficacy of therapeutic regimens for prion disease, and possibly also for deferring blood and organ donors that may be at risk of transmitting prion infections.

Chemically induced accumulation of GAGs delays PrP(Sc) clearance but prolongs prion disease incubation time

Prion diseases are a group of fatal neurodegenerative diseases affecting humans and animals. The only identified component of the infectious prion is PrP(Sc), an aberrantly folded isoform of PrP(C). Glycosaminoglycans, which constitute the main receptor for prions on cells, play a complex role in the pathogenesis of prion diseases. For example, while agents inducing aberrant lysosomal accumulation of GAGs such as Tilorone and Quinacrine significantly reduced PrP(Sc) content in scrapie-infected cells, administration of Quinacrine to prion-infected subjects did not improve their clinical status. In this study, we investigated the association of PrP(Sc )with cells cultured with Tilorone. We found that while the initial incorporation of PrP(Sc) was similar in the treated and untreated cells, clearance of PrP(Sc) from the Tilorone-treated cells was significantly impaired. Interestingly, prolonged administration of Tilorone to mice prior to prion infection resulted in a significant delay in disease onset, concomitantly with in vivo accumulation of lysosomal GAGs. We hypothesize that GAGs may complex with newly incorporated PrP(Sc) in lysosomes and further stabilize the prion protein conformation. Over-stabilized PrP(Sc) molecules have been shown to comprise reduced converting activity.

Recent Developments in Prion Disease Research: Diagnostic Tools and In Vitro Cell Culture Models

After prion infection, an abnormal isoform of prion protein (PrP(Sc)) converts the cellular isoform of prion protein (PrP(C)) into PrP(Sc). PrP(C)-to-PrP(Sc) conversion leads to PrP(Sc) accumulation and PrP(C) deficiency, contributing etiologically to induction of prion diseases. Presently, most of the diagnostic methods for prion diseases are dependent on PrP(Sc) detection. Highly sensitive/accurate specific detection of PrP(Sc) in many different samples is a prerequisite for attempts to develop reliable detection methods. Towards this goal, several methods have recently been developed to facilitate sensitive and precise detection of PrP(Sc), namely, protein misfolding cyclic amplification, conformation-dependent immunoassay, dissociation-enhanced lanthanide fluorescent immunoassay, capillary gel electrophoresis, fluorescence correlation spectroscopy, flow microbead immunoassay, etc. Additionally, functionally relevant prion-susceptible cell culture models that recognize the complexity of the mechanisms of prion infection have also been pursued, not only in relation to diagnosis, but also in relation to prion biology. Prion protein (PrP) gene-deficient neuronal cell lines that can clearly elucidate PrP(C) functions would contribute to understanding of the prion infection mechanism. In this review, we describe the trend in recent development of diagnostic methods and cell culture models for prion diseases and their potential applications in prion biology.

Urine from scrapie-infected hamsters comprises low levels of prion infectivity

The question of whether prion diseases can be transmitted by body fluids has important epidemiological, environmental and economical implications. In this work, we set to investigate whether urine collected from scrapie-infected hamsters can transmit fatal or subclinical infectivity to normal hamsters. After prolonged incubation times ranging from 300 to 700 days, a small number of animals inoculated with scrapie urine succumbed to scrapie disease, and several asymptomatic hamsters presented low levels of PrP(Sc) in their brains. In addition, most of the asymptomatic hamsters inoculated with scrapie urine, as opposed to those inoculated with normal urine, presented extensive gliosis as well as protease-resistant light chain IgG in their urine, a molecule shown by us and others to be a surrogate marker for prion infection. Our results suggest that urine from scrapie-infected hamsters can transmit a widespread subclinical disease that in some cases develops into fatal scrapie.