Studies show that Angiopoietin-2 is a strong predictor in COVID-19 patients

Two research teams find that increased levels of the proinflammatory cytokine Angiopoietin-2 predicts transfer to the ICU and is responsible for hypercoagulation observed in critically ill COVID-patients.

Studies:

Angiopoietin-2 as a marker of endothelial activation is a good predictor factor for intensive care unit admission of COVID-19 patients. Smadja DM et al., Angiogenesis, 2020;1-10. Full text

Elevated Angiopoietin-2 inhibits thrombomodulin-mediated anticoagulation in critically ill COVID-19 patients. Hultstrom M et al., MedRxiv preprint server, 2021. Full text

Click here for a summary of the findings.

Background

SARS-CoV-2 is the causative agent of the coronavirus respiratory disease COVID-19. It has a diverse range of symptoms and may cause severe illness, in particular in patients with cardiovascular risk factors (1).

Endothelial damage and inflammation in SARS-CoV-2 infection

The inflammatory cytokine storm occurring in COVID-19 patients, leads to the recruitment of leukocytes which damage the capillary endothelium. The endothelial damage and inflammation in several organs in SARS-CoV-2 infection is a direct consequence of viral involvement and of the host inflammatory response (2).
Despite the routine thrombosis prophylaxis as standard of care treatment, the major COVID-19 complication is the hyperactivation of the coagulation system indicating a poor prognosis among COVID-19 patients in intensive care (3).

Angiopoietin-2 (ANG2) is a soluble marker of endothelial activation

Angiopoietin-2 is an angiogenesis regulator that can be rapidly released by the activated endothelium upon thrombin or inflammatory cytokines. ANG2 induces inflammation and vascular hyperpermeability and correlates with adverse outcomes in several critical care syndromes (4, 5).

Angiopoietin-2 is a crucial factor to predict transfer to the ICU

In COVID-19 patients, ANG2 was recently reported by Smadja and colleagues to be a relevant factor to predict transfer to the ICU as it was associated with poor lung compliance (6). Thus, showing that endothelial activation reinforces the hypothesis of a COVID-19-associated microvascular dysfunction.

Angiopoietin-2 inhibits anticoagulation in critically ill COVID-19 patients

Hulstrom and colleagues recently demonstrated that ANG2 levels in critically ill COVID-19 patients correlate with disease severity, hypercoagulation, and mortality. In addition, the researchers provided novel in vivo evidence for a direct role for ANG2 in coagulation through binding to and inhibition of thrombomodulin-mediated anticoagulation. The scientists suggest that inhibition of ANG2 might be beneficial for treating critically ill COVID-19 patients, as well as other patients with hypercoagulation (7).

About the Angiopoietin ELISA

Low sample volume – only 10µl needed
Assay range optimized for clinical samples
Ready to use standards and 2 controls included
Highly specific epitope mapped capture and detection antibodies

The human Angiopoietin-2 ELISA kit was developed and manufactured by Biomedica

Literature

Clinical course and risk factors for mortality of adult inpatients with COVID-19 in Wuhan, China: a retrospective cohort study. Zhou F et al., Lancet, 2020; 395(10229):1054-1062.
Endotheliitis in COVID-19. Varga S. Der Pathologe, 2020; 41(Suppl 2):99-102.
COVID-19 and coagulation: bleeding and thrombotic manifestations of SARS-CoV-2 infection. Al-Samkari H et al., Blood, 2020:136, 489-500.
Role of Angiopoietin-2 in Vascular Physiology and Pathophysiology. Akwii RG et al., Cells, 2019; 8(5): 471.
Circulating angiopoietin-2 and the risk of mortality in patients with acute respiratory distress syndrome: a systematic review and meta-analysis of 10 prospective cohort studies. Li F et al., Therapeutic advances in respiratory disease, 2020; 14, 1753466620905274.
Angiopoietin-2 as a marker of endothelial activation is a good predictor factor for intensive care unit admission of COVID-19 patients. Smadja DM et al., Angiogenesis, 2020;1-10.
Elevated Angiopoietin-2 inhibits thrombomodulin-mediated anticoagulation in critically ill COVID-19 patients. Hultstrom M et al., MedRxiv preprint server, 2021.

Eagle News

Osteoclasts Regulate Sclerostin Expression and Bone Formation

by Eagle Biosciences

Sclerostin expression in trabecular bone is down-regulated by osteoclasts

Scientific Reports

Bone tissues have trabecular bone with a high bone turnover rate and cortical bone with a low turnover. Expression of sclerostin by osteocytes works to inhibit bone formation. A study performed recently aimed to evaluate the relationship between the secretion of sclerostin by osteocytes and the secretion of leukemia inhibitory factor (LIF) by osteoclasts. It was found that LIF secretion effectively suppresses sclerostin expression and promotes bone formation.

Read the full article here.

Eagle Biosciences offers a sensitive and reliable assay for the detection of sclerostin in serum and plasma samples:

Sclerostin ELISA Assay Kit

Free Soluble RANKL ELISA Assay Kit

If you are looking for any other specific Bone Monitoring related products or if you have questions about our offerings, contact us here.

Publication Spotlight

Multiple Endocrinology Assays Featured in a New Study for Type 1 Diabetes

by Eagle Biosciences

EagleBio Endocrinology

Confirmation and Identification of Biomarkers Implicating Environmental Triggers in the Pathogenesis of Type 1 Diabetes

Frontiers in Immunology

Numerous ELISA Assay Kits from our endocrinology line were used in a recent study published out of the University of Nebraska Medical Center in Omaha, Nebraska. These kits were used to analyze blood plasma for biomarkers that could implicate environmental triggers for the pathogenesis of Type 1 Diabetes. These kits included;

Anti-GAD ELISA Assay Kit

Anti-IA2 ELISA Assay Kit

Anti-tTG IgA ELISA Assay Kit

High Sensitive Anti-TPO ELISA Assay Kit

Abstract

Multiple environmental triggers have been proposed to explain the increased incidence of type 1 diabetes (T1D). These include viral infections, microbiome disturbances, metabolic disorders, and vitamin D deficiency. Here, we used ELISA to examine blood plasma from juvenile T1D subjects and age-matched controls for the abundance of several circulating factors relevant to these hypotheses. We screened plasma for sCD14, mannose binding lectin (MBL), lipopolysaccharide binding protein (LBP), c-reactive protein (CRP), fatty acid binding protein 2 (FABP2), human growth hormone, leptin, total adiponectin, high molecular weight (HMW) adiponectin, total IgG, total IgA, total IgM, endotoxin core antibodies (EndoCAbs), 25(OH) vitamin D, vitamin D binding protein, IL-7, IL-10, IFN-γ, TNF-α, IL-17A, IL-18, and IL-18BPa. Subjects also were tested for prevalence of antibodies targeting adenovirus, parainfluenza 1/2/3, Coxsackievirus, cytomegalovirus, Epstein-Barr virus viral capsid antigen (EBV VCA), herpes simplex virus 1, and Saccharomyces cerevisiae. Finally, all subjects were screened for presence and abundance of autoantibodies targeting islet cell cytoplasmic proteins (ICA), glutamate decarboxylase 2 (GAD65), zinc transporter 8 (ZNT8), insulinoma antigen 2 (IA-2), tissue transglutaminase, and thyroid peroxidase, while β cell function was gauged by measuring c-peptide levels. We observed few differences between control and T1D subjects. Of these, we found elevated sCD14, IL-18BPa, and FABP2, and reduced total IgM. Female T1D subjects were notably elevated in CRP levels compared to control, while males were similar. T1D subjects also had significantly lower prevalence of EBV VCA antibodies compared to control. Lastly, we observed that c-peptide levels were significantly correlated with leptin levels among controls, but this relationship was not significant among T1D subjects. Alternatively, adiponectin levels were significantly correlated with c-peptide levels among T1D subjects, while controls showed no relationship between these two factors. Among T1D subjects, the highest c-peptide levels were associated with the lowest adiponectin levels, an indication of insulin resistance. In total, from our examination we found limited data that strongly support any of the hypotheses investigated. Rather, we observed an indication of unexplained monocyte/macrophage activation in T1D subjects judging from elevated levels of sCD14 and IL-18BPa. These observations were partnered with unique associations between adipokines and c-peptide levels among T1D subjects.

To learn more and read the full publication, click here.

For a full list of Eagle Bioscience’s Endocrinology line of ELISA kits click here.

Eagle News

Urinary 5-HIAA a Potential Predictor of Acute Appendicitis

by Eagle Biosciences

Biomarker of urinary 5-HIAA as a valuable predictor of acute appendicitis

Science Direct

Acute appendicitis is one of the most common causes of severe acute abdominal pain globally. Increased levels of 5-Hydroxyindole acetic acid (5-HIAA), a metabolite of serotonin, in urine has been associated with acute appendicitis due to the densely packed serotonin-containing cells in the appendix. A study performed recently aimed to evaluate and determine the significance of 5-HIAA as a diagnostic marker.

Read the full article here.

Eagle Biosciences offers a sensitive and reliable assay for the detection of 5-HIAA in urine samples:

5-HIAA ELISA Assay Kit

Serotonin ELISA Assay Kit

Serotonin Ultrasensitive ELISA Assay Kit

If you are looking for any other specific 5-HIAA related product or if you have questions about our offerings, contact us here.

Eagle News

Studies Show that Neuropilin-1 Could Play Role in Transmission of COVID-19

by Eagle Biosciences

Two Independent Research Teams Find Possible Link Between Neuropilin-1 and SARS-CoV-2 Transmission

Neuropilin-1 (NRP1) is an essential transmembrane cell surface receptor acting primarily as a co-receptor for various ligands (i.e. VEGF, Semaphorins). Due to alternative splicing or shedding, the extracellular region can be released into circulation as soluble Neuropilin-1. NRP1 functions in many key biological processes including the neuronal, cardiovascular and the immune system. The virus SARS-CoV-2 is the causative agent of the coronavirus disease COVID-19 NRP1 is expressed in multiple cell types in the body but occurs primarily on cells in the lung, nose and brain (i.e. respiratory and olfactory epithelium as well as in the CNS). SARS CoV 2 enters the host cells by its spike proteins mainly through its binding to the angiotensin converting enzyme 2 (ACE2).

Click here for summary of findings.

Studies:

Neuropilin-1 facilitates SARS-CoV-2 cell entry and provides a possible pathway into the central nervous system. Cantuti-Castelvetri L et al., Science 13 Nov, 2020; Vol. 370, Issue 6518, pp. 856-860. Full publication.

Neuropilin-1 is a host factor for SARS-CoV-2 infection. Daly JL et al., Science, 13 Nov 2020; Vol. 370, Issue 6518, pp. 861-865. Full publication.

About the Neuropilin-1 ELISA:

Only assay that measures free and ligand bound soluble NRP1
Low sample volume – only 10µl needed
Highly specific using epitope mapped antibodies
Rigorously validated according to international guidelines

Product Announcement

Eagle Biosciences Adds New VEGF ELISA

by Eagle Biosciences

Eagle Biosciences is now offering a new Human VEGF ELISA Kit from Biomedica. The VEGF ELISA Assay Kit is intended for the quantitative determination of human VEGF in serum, EDTA plasma, and citrate plasma.

VEGF ELISA Highlights:

DAY Test – results in 4.5 h
High sensitivity – measurable values in both serum and plasma
RELIABLE- rigorously validated according to FDA/ICH/EMA guidelines
READY to use – calibrators and controls included
EXCELLENT correlation to existing methods
SMALL sample size – only 10µl sample / well required

Areas of interest:

Cancer
Metabolic disease (diabetes and diabetic kidney disease, diabetic retinopathy, obesity)
Retinal Diseases
Autoimmune & inflammatory disease (rheumatoid arthritis, psoriasis, psoriatic arthritis)
Heart and cardiovascular disease
Skeletal bone formation and bone repair

About VEGF

Vascular endothelial growth factor (VEGF or VEGF-A), is a growth hormone secreted by endothelial cells, ﬁ broblasts, smooth muscle cells, platelets, macrophages, and many other cell types. It belongs to the cysteine-knot growth factor superfamily (1) and has a molecular weight of about 40 kDa. Currently, 17 different VEGF isoforms have been described to be expressed from one single gene. They are produced by alternative promoter usage/initiation or alternative splicing/proteolysis after protein translation. The N-terminal region is responsible for receptor binding and conserved among all VEGF isoforms. In contrast, residues of the C-terminus differ between isoforms and determine protein length and properties: binding to co-receptor Neuropilin-1 (NRP1) or to extracellular matrix (ECM), agonist/antagonist of angiogenesis. Most isoforms result from the common transcripts: VEGF111, VEGF121, VEGF145, VEGF165, VEGF189 and VEGF206. Additionally, a third VEGF variant (VEGFAx), that demonstrates pro- and anti-apoptotic properties, was described. Thus, vascularization is tightly controlled by the balance of various splice variants, their availability and concentration, whereas isoforms linked to the ECM constitute a reservoir of VEGF that can quickly be shed to circulating forms. One of the most potent pro-angiogenic isoforms is VEGF165a. After secretion, 50-70% of VEGF165a is attached to the extracellular matrix (via heparin binding site), the rest is freely diffusible. It is the most abundant isoform and enhances signaling over the VEGFR2 receptor by additionally binding to its co-receptor Neuropilin-1. VEGF A isoforms are glycosylated, homodimeric proteins. Two anti-parallel monomers are linked by intermolecular disulfide bonds whereas eight cysteine residues form a knot-like structure at one end of each monomer. However, heterodimerization with PLGF has been described as well.

Contact us for more information about this product.

Product Announcement

New LRG ELISA Available from Biomedica

by Eagle Biosciences

LEUCINE-RICH ALPHA-2-GLYCOPROTEIN (LRG) ELISA Now Available!

Austrian supplier Biomedica has released a new ELISA, the Leucine-Rich Alpha-2-Glycoprotein or LRG for short. The LRG ELISA Assay kit is intended for the quantitative determination of human LRG in serum, EDTA plasma, heparin plasma, and citrate plasma.

Human LRG ELISA highlights:

DAY Test – results in 3.5 h
RELIABLE- rigorously validated according to FDA/ICH/EMA guidelines
ALL reagents included -controls and sufficient amounts of buffers
EXCELLENT correlation to existing methods

Size: 1×96 wells
Sensitivity: 0.26 ng/ml
Standard Range: 0 – 64 ng/ml
Incubation Time: 3.5 hours
Sample Type: Serum, Plasma
Sample Size: 100 µl pre-diluted sample / well (5 µl sample)

About LRG

LRG (leucine-rich alpha-2-glycoprotein) is a glycoprotein with a molecular mass of 38.2 kDa. It is encoded by the human gene LRG-1 which is mapped on chromosome 19 at the cytogenetic band 19p13.3. The protein LRG (or also named LRG1) runs at approximately 50 kDa under reducing conditions, as it contains a carbohydrate content of 23%. LRG is the founding member of the family of leucine-rich repeat proteins. The mature protein consists of 312 amino acids, from Val36 to Gln347, with a leucine content of 66 amino acids. LRG is folded to eight leucine-rich repeat (LRR) domains of 22 amino acid length, and a C-terminal LRRCT domain with 49 amino acid length. Human LRG shows 62.5% sequence identity with mouse LRG, and 60.7% with rat LRG.

LRG binds to the TGFβ accessory receptor endoglin, and in the presence of TGFβ1 this leads to the induction of the TβRII-ALK1-Smad1/5/8 signaling pathway. TGFβ1 therefore promotes binding of LRG to the proangiogenic ALK1 but inhibits the interaction with angiostatic ALK5. Induced signaling leads to endothelial cell proliferation and blood vessel outgrowth.

Like many other family members of the leucine-rich repeat (LRR) family, LRG has multiple binding partners. LRG directly interacts with the mitochondrial electron transfer protein cytochrome c, whereas the physiological relevance of this interaction is not yet known. LRG further binds to TGFβ1, the most frequently expressed TGFβ isoform.

The tissue distribution of LRG varies, with high-level expression in the liver, lower expression in the heart, and minimal expression in spleen and lung. LRG is expressed during hematopoiesis. It plays a role in the innate immune system as it is upregulated during neutrophil differentiation; LRG is packed into peroxidase-negative granules of human neutrophils and then secreted upon activation to modulate the microenvironment. Differential expression of LRG is further associated with certain carcinomas, neurodegenerative disease, aging or autoimmune disease. In addition, studies have demonstrated an association between cardiac remodeling (hypertrophy, fibrosis, abnormal vasculature, heart failure) and reduced expression of LRG.

LRG is involved in cell proliferation and immune response, in cell migration, neovascularization and apoptosis. It is a proangiogenic factor which is involved in the regulation of the TGFβ signaling pathway. Up-regulation of LRG is described in response to acute phase response in hepatocytes.

LRG is potentially a biomarker for a variety of diseases e.g. as inflammatory biomarker for autoimmune diseases such as rheumatoid arthritis and inflammatory bowel disease. Numerous groups have shown that LRG is increased in various immune-related diseases such as psoriasis, juvenile idiopathic arthritis, Kawasaki disease, appendicitis, and cancers, indicating that LRG elevation is not only limited to autoimmune diseases. In addition, LRG may serve as a biomarker for several other disease conditions such as heart failure, and diabetes-related complications. Plasma Leucine-Rich α-2-Glycoprotein has also been demonstrated to predict cardiovascular disease risk in end-stage renal disease. Leucine-rich α-2-glycoprotein is highly expressed in the brain and it is possible to distinguish idiopathic normal pressure hydrocephalus (iNPH) from other neurodegenerative diseases such as Alzheimer disease by measuring LRG in cerebrospinal fluid.

To learn more about this product click here or contact us with questions

Uncategorized

SARS-CoV-2 ELISA Used in Icelandic Study!

by Eagle Biosciences

Epitope Diagnostics Inc. New COVID-19 IgG and IgM ELISA Featured in Icelandic Study on Humans Immune Response to SARS-CoV-2 Exposure

A study has recently been published in the New England Journal of Medicine titled Humoral Immune Response to SARS-CoV-2 in Iceland by D.F. Gudbjartsson, et. al. This study takes a look at the semi-long term immune response of the COVID-19 respiratory infection. 30,576 patient samples were tested for both IgG and IgM antibodies using both q-PCR and ELISA methods. The ELISA’s used in this study were the Coronavirus COVID-19 IgG ELISA Assay and Coronavirus COVID-19 IgM ELISA Assay Kit offered by Eagle Biosciences. The results of this study showed that IgM anti-N antibody levels increased rapidly soon after diagnosis and then fell rapidly and were generally not detected after 2 months. IgG anti-N and anti-S1 antibody levels increased during the first 6 weeks after diagnosis and then decreased slightly, indicating that antiviral antibodies against SERS-CoV-2 did not decline within 4 months after diagnosis. With respect to clinical characteristics, antibody levels were most strongly associated with hospitalization and clinical severity, followed by clinical symptoms such as fever, maximum temperature reading, cough, and loss of appetite. Severity of these individual symptoms, with the exception of loss of energy, was associated with higher antibody levels.

More research still needs to be conducted to understand the full immune response over time. However, this is a great step in the development of how this virus works and how the world will be able to overcome it.

To learn more and read the full publication, click here.

To view Eagle Biosciencs extensive selection of SARS-CoV-2 Assays and other products, click here

How Does COVID-19 Effect Your Central Nervous System?

by Eagle Biosciences

A new article published by Nelly Kanberg, et al. titled Neurochemical evidence of astrocytic and neuronal injury commonly found in COVID-19 has set out to study how COVID-19 impacts the central nervous system. It’s already known how this novel coronavirus effects the respiratory system, but does the body’s inflammatory response to this virus cause lasting effects to the nervous system?

For this study, two biomarkers in human plasma were measured; neurofilament light chain protein (NfL) and glial fibrillary acidic protein (GFAP). The samples came from patients who had mild, moderate or severe cases of COVID-19 (n=47). Of those 47 patients, the ones who had a severe case of COVID-19 showed higher concentrations of GFAP and NfL.

Glial Fibrillary Acidic Protien, or GFAP for short, is a known biomarker in the central nervous system (CNS) that is typically studied in those with brain injuries. When a brain injury occurs (concussion, retinal stess, tumors, etc.), GFAP is released into the blood stream and helps determine the severity of the injury. The results of this study help support and determine the relationship between COVID-19 and potentially lasting neural injuries.

To read this article in full, click here.

To learn more about how to measure GFAP, click here or contact us with your questions

Uncategorized

New iLite Cells Now Available!

by Eagle Biosciences

Svar Life Sciences has Added Two New assay ready cells to their iLite® Product Line!

iLite® C5a Assay Ready Cells

The iLite^® C5a Assay Ready Cells can be used for the quantification of C5a activity, and for determination of inhibitory activity against either C5a itself or against the C5a receptor in test samples, including human serum.

Read Product Specifications Here

iLite^® RANKL Assay Ready Cells

The iLite^® RANKL Assay Ready Cells can be used for the quantification of RANKL activity, RANKL inhibitor activity or immunogenicity studies and determination of neutralizing antibody response against RANKL inhibitors in test samples, including human serum.

Read Product Specifications Here

As always, contact us with any questions you have and someone from our sales team will be happy to assist you!