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EagleBio Biomarker Spotlight:  Homoarginine


 

 

 

What is Homoarginine?

Homoarginine
is a non-essential cationic amino acid, which is formed from lysine and it is a
precursor of nitric oxide (NO).  This
amino acid has been thought to be involved in increasing the availability of NO
which is the basis of its many roles including enhancing endothelial and myocardial
functions.In vitro and in vivo, Homoarginine shows characteristics similar to arginine. Epidemiological
investigations in two large independent cohorts, namely the German diabetes
dialysis (4D)  study and the Ludwigshafen Risk and Cardiovascular Health
(LURIC)  study have identified homoarginine as useful predictor of cardiovascular
events and mortality.

In other recent
studies, a correlation of increasing homoarginine levels to increasing age was
noted when observing healthy children and adolescents. This age-dependent increase in plasma
concentration is theorized that it is caused as a result of gradual maturation
of the pathways controlling homoarginine metabolism.  Despite these results, homoarginine and
ornithine do not appear to be linked with carotid vascular structure in healthy
children and adolescents.

Beyond
cardiovascular implications, homoarginine concentrations have also been found
to be directly correlated with kidney function and are significantly associated
with the progression of chronic kidney disease (CKD).
Low homoarginine
concentrations might be an early indicator of kidney failure and a potential
target for the prevention of disease progression but this theory needs further
exploration and investigation. The
results from Ravani et al. reveal that homoarginine could be a useful marker
for monitoring hemodialysis patients.  In
fact, these results may provide the foundation and basis of designing such clinical
trials. 

 

Why Measure Homoarginine?

Homoarginine
as described above has many roles and potential effects on various functions
and organs in the body as it has been demonstrated from numerous studies that
it has implications in endothelial, cardiovascular, and renal events. Other specific areas of research that
homoarginine metabolism have been linked to are ischemic strokes and pregnancy
pathologies such as preeclampsia.This analyte continues to be the focus of numerous studies and fields of
research.

 

Related Kits:

Homoarginine ELISA Assay kit

Cardiovascular Assay Kits


References:

  1. Choe, CU et al. “Homoarginine levels are regulated by
    L-arginine: glycine amidinotransferase and affect outcome: results from
    human and murine studies.” Circulation 2013; 128 (13): 1451-61. https://www.ncbi.nlm.nih.gov/pubmed/24004504
  2. Drechler, Christiane et al. “Homoarginine and
    Progression of Chronic Kidney Disney: Results from the Mild to Moderate
    Kidney Disease Study.” PLOS One 2013; DOI: 10.1371/journal.pone.0063560. https://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0063560#s1
  3. Jazwinska-Kozuba et al. “Opposite Associations of
    Plasma Homoarginine and Ornithine with Arginine November 2013; 14,
    21819-21832in Healthy Children and Adolescents”. International Journal of
    Molecular Sciences. https://www.mdpi.com/1422-0067/14/11/21819
  4. Khalil, AA et al. “Asymmetric dimethylarginine,
    arginine and Homoarginine at 11-13 weeks’ gestation and preeclampsia: a
    case-control study.” Journal of Human Hypertension, 2013; 27, 38-43. https://www.readcube.com/articles/10.1038/jhh.2011.109
  5. Marz, Winfried et al. “Homoarginine, Cardiovascular
    Risk, and Mortality.” Circulation , 2010; 112: 967-975. https://circ.ahajournals.org/content/122/10/967.long
  6. Meinitzer, Andreas et al. “Homoargine: a new
    cardiovascular risk marker in hemodialysis patients.” Journal of
    Laboratory Medicine 2011; 35(3): 153-159. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3143829/
  7. Ravani, Pietro et al. “Homoarginine and Mortality in
    Pre-Dialysis in Chronic Kidney Disease (CKD) Patients.”PLOS One 2013;
    DOI: 10.1371/journal.pone.0072694.g003. https://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0072694

EagleBio Biomarker Spotlight:  ADMA


 

 

What is ADMA?

ADMA the abbreviation for asymmetric dimethylarginine and it is endogenous molecule which can be detected in human blood and urine. It shows structural homology to the amino acid L-arginine, and it acts as an inhibitor of nitric oxide (NO) synthesis. (5,6)

In fact, various studies performed in vitro and in vivo have confirmed and demonstrated that ADMA concentration-dependently inhibits NO production.(3,5)  Böger RH et al. 2004 study discusses the mechanism of the modulation of NOS activity. This study describes how the inhibition of the enzyme that inactivates ADMA, dimethylarginine dimethylaminohydrolase (DDAH), thereby elevating ADMA levels and causing vasoconstriction of isolated arterial rings in vitro. (2)  DDAH’s role in degradation of ADMA is the major pathway for its elimination however, a small amount is eliminated by renal excretion. (4)

Pathophysiological Role of ADMA
The vascular endothelium plays a central role in the regulation of vascular structure and function, mainly due to the formation of endothelium-derived nitric oxide (NO). NO has been named an “endogenous anti-atherogenic molecule” due to its diverse regulatory functions in vascular homeostasis. In fact, ADMA has been found to cause vasoconstriction when it is infused intraarterially. NO is formed by the enzyme NO synthetase (NOS) from the amino acid precursor L-arginine and it plays a large role within cardiovascular system. NOS activity can be down-regulated by asymmetric dimethylarginine (ADMA), an endogenous inhibitor of NOS as described above. (3,5,6)


In past studies, patients with end-stage chronic renal failure and have little or no urine output, elimination is thus blocked and as a result circulating concentrations of ADMA rise appropriately to inhibit NO synthesis. The accumulation of ADMA is thought to lead to impaired NOS synthesis as described above this is theorized to be a contributing factor to hypertension and immune dysfunction associated with chronic renal failure. (4)  In addition to ADMA’s effects on vasodilation, a rise in circulating ADMA levels lead to an increased resting vascular tone. It also enhances several pro-atherogenic mechanisms including platelet aggregation and adherence of monocytes, proliferation of vascular smooth muscle cell, as well as extracellular matrix formation. (4)

 


The effects of ADMA on NO synthesis and NO-mediated pathophysiological processes have been described in numerous experimental studies. Moreover, elevated ADMA levels in plasma have been found in clinical studies including patients with hypercholesterolemia, hypertension, chronic heart failure, chronic renal failure and other internal disorders. Recent prospective and cross-sectional studies indicated that elevated ADMA levels are a risk factor for future cardiovascular eve
nts and total mortality. ADMA may have diagnostic relevance as a novel cardiovascular risk marker. (2,3)



Diseases Associated with Elevated ADMA Levels:

  • Coronary Artery Disease
  • Chronic Renal Failure and Hemodialysis Treatment
  • Peripheral Arterial Occlusive Disease
  • Chronic Heart Failure
  • Hypertensive patients
  • Diabetes Mellitus
  • Lipid Disorders
  • Preeclampsia
  • Erectile Dysfunction


What Methods can be used to Measure ADMA?

Eagle Biosciences offers many options for researchers looking to measure ADMA:

  • ADMA ELISA Assay Kit
  • ADMA Ultrasensitive ELISA Assay Kit
  • Mouse/Rat ADMA ELISA Assay Kit
  • ADMA / Arginine ELISA Assay Kit
  • SDMA ELISA Assay Kit
  • Homoarginine ELISA Assay Kit

 

References:

  1. Antoniades,
    C et al. “ Asymmetrical dimethylarginine regulates endothelial function in
    methionine-induced but not in chronic homocystinemia in humans: effect of
    oxidative stress and proinflammatory cytokines.”
    Am. J. Clin. Nutr. 2006; 84: 781-788. https://ajcn.nutrition.org/content/84/4/781.full
  2. Böger
    RH et al. “Asymmetric Dimethylarginine, an Endogenous Inhibitor of Nitric Oxide
    Synthase, Explains the “l-Arginine Paradox” and Acts as a Novel Cardiovascular
    Risk Factor.”
    J. Nutr. 2004; 134 no. 10 2842S-2847S.https://jn.nutrition.org/content/134/10/2842S.long
  3. Böger
    RH et al. “Asymmetric dimethylarginine: a novel risk factor for endothelial
    dysfunction. Its role in hypercholesterolemia.”
    Circulation 1998; 98: 1842 – 1847.https://cardiovascres.oxfordjournals.org/content/59/4/824.full.pdf+html
  4. Krempl
    TK et al. “Elevation of asymmetric dimethylarginine (ADMA) in patients with
    unstable angina and recurrent cardiovascular events.” Eur. Heart J. 2005; 26:
    1846-1851.
    https://eurheartj.oxfordjournals.org/content/26/18/1846.full
  5. Vallance
    P. et al. “ Accumulation of an endogenous inhibitor of NO synthesis in chronic
    renal failure”.
    Lancet 1992; 339: 572
    – 575.
    https://www.ncbi.nlm.nih.gov/pubmed/1347093?dopt=Abstract
  6. Vallance
    P. et al. “ Endogenous dimethyl-arginine as an inhibitor of nitric oxide
    synthesis”.
    J. Cardiovasc. Pharmacol.
    1992; 20 (Suppl. 12): S60 – S62.
    https://jn.nutrition.org/content/134/10/2842S.long

Eagle Biosciences introduces new ultrasensitive Steroid Saliva ELISA kits that will allow for quantification of many samples that were previously undetectable with a traditional steroid saliva assay. The list of new immunoassays includes Ultrasensitive Salivary Cortisol ELISA and Ultrasensitive Salivary DHEA-S ELISA with Ultrasensitive Salivary Testosterone ELISA, Ultrasensitive Salivary Progesterone ELISA, and Ultrasensitive Salivary Estradiol ELISA coming soon.

Dan Keefe, President of Eagle, is excited about the new products, “We are thrilled to offer the new assays as they could change the way researchers measure salivary Cortisol, Testosterone, Progesterone, Estradiol, and DHEA-S. In addition to their sensitivity, the steroid kits are easy to run and will provide results in less than 3 hours.”

For more information on these kits or any of the products from Eagle Biosciences, visit our website at www.EagleBio.com or call us at 617-419-2019.

Eagle Biosciences, Inc. is proud to introduce a new Mouse Monoclonal Antibody Isotyping ELISA kit. The Mouse Monoclonal Antibody (mAb) Isotyping assay kit is designed for the quick and easy identification of both mouse immunoglobulin subclass and light chain. Utilizing a simple 96 well (8×12) ELISA format, up to 12 individual samples can be determined per 96 strip-well plate for heavy chain anti-IgG1, IgG2a, IgG2b, IgG3, IgA, and IgM as well as light chain kappa and lambda. One sample is used per strip utilizing a traditional ELISA plate reader.

“This ELISA kit has excellent specificity for each subtype and results can be produced in about a hour while keeping costs per sample below $6.”said Dan Keefe, President of Eagle,”This product is just the tip of the iceberg for Eagle. We are thrilled about this product launch because it represents the first of a line of Eagle developed assays that will isotype individual mouse monoclonal antibody subclasses.” Eagle expects to introduce individual ELISA based assays for the mouse monoclonal antibody isotypes as soon as this summer.”

The Eagle Mouse Monoclonal Antibody Isotyping ELISA kit is available in convenient 1 plate, 5 plate, or custom bulk sizes and is priced very competitively. For more information on this kit or any of the products from Eagle Biosciences, visit the website at www.EagleBio.com or call at 866-411-8023.

Eagle Biosciences, Inc. has announced the product launch of two new catecholamine ELISA kits. The catecholamine kits are Vanillylmandelic Acid (VMA) ELISA and Homovanillic Acid (HVA) ELISA which will be the most sensitive and highly specific on the market. Both the VMA ELISA and HVA ELISA include a full standard set with a dynamic range of 0.0625 -8 µg/ml for VMA and 0.125-16 µg/ml for HVA.

Dan Keefe, President of Eagle Biosciences, is very excited about these new ELISA kits, “This is an exciting time for Eagle. We just launched the innovative Mouse Monoclonal Antibody Isotyping ELISA in April 2011 and now we can introduce the Vanillylmandelic Acid (VMA) and Homovanillic Acid (HVA) ELISA kits. They are developed and manufactured in the USA, are simple to run, and yield quantifiable results in under 2 hours.”

For more information on the VMA ELISA, the HVA ELISA, or any of the products from Eagle Biosciences, visit the website at www.EagleBio.com or call at 866-411-8023.

Eagle Biosciences, Inc. is pleased to announce the product launch of 7 new Vitamin HPLC Assay Kits. These high quality kits provide results in under an hour while cost per sample remains affordable. Included in this launch are: Vitamin A & Vitamin E HPLC Assay, Vitamin B1 (Thiamine Pyrophosphate) HPLC Assay, Vitamin B2 (Riboflavin) HPLC Assay, Vitamin B6 HPLC Assay, Vitamin C HPLC Assay, 25-OH Vitamin D HPLC Assay, and Vitamin K1 HPLC Assay. To complete the product offerings, HPLC columns and controls are also available through Eagle Biosciences.

Dan Keefe, President of Eagle Biosciences, is thrilled about the launch of these kits, “This is an exciting time for Eagle. In the last few months, we have launched the innovative Mouse Monoclonal Antibody Isotyping ELISA along with the unique Cytokeratin Assays from IDL Biotech and now we are proud to introduce these high quality vitamin assays that are as simple to run as they are cost effective.”

Eagle anticipates offering promotional pricing in the coming months for researchers measuring Vitamin A, Vitamin B1, Vitamin B2, Vitamin B6, Vitamin C, 25-OH Vitamin D, Vitamin E, and Vitamin K1. These assay kits are currently for research use only.

Eagle Biosciences announces the product launch of 3 new assays to measure ADMA, SDMA, and L-Arginine in serum and plasma samples. The 3 ELISA kits include ADMA ELISA, the most widely published ADMA assay on the market, SDMA ELISA with a sensitivity of 0.05 µmol/L, and ADMA & Arginine ELISA which is intended for the quantitative determination of both endogenous ADMA as well as L-Arginine in EDTA-Plasma on 2 different 96-well microplates.

Previously, ADMA was measured by HPLC or LC-MS methods that were focused on the chromatographic separation of the structurally similar but functionally different SDMA and ADMA isomers. These HPLC methods were successful, but were largely expensive and laborious. This ADMA ELISA kit was developed with a very specific and sensitive rabbit anti-ADMA antibody that allows for excellent correlation with these LC-MS methods. ADMA is the abbreviation for asymmetric dimethylarginine while SDMA is the abbreviation for symmetric dimethylarginine.

“Eagle is very excited to now offer the ADMA, SDMA, and the new ADMA / Arginine ELISA kits”, said Dan Keefe, President of Eagle Biosciences. “These are the best ADMA assays in the world because they are easy to perform with virtually no cross reactivity to other forms of arginine while still correlating with LC-MS. This is great news for researchers.”

Eagle is offering promotional pricing for the next few months for researchers measuring ADMA, SDMA, or Arginine. These assay kits are currently for research use only. Check out the Eagle website www.EagleBio.com or call 866-411-8023 for full details.

Eagle Biosciences is excited to announce the introduction of a new assay for 25-OH Vitamin D by enzyme linked immunoassay (ELISA). Adding to their menu of more than 200 Assays, Eagle adds the 25-Hydroxy Vitamin D ELISA to other vitamin assays for Vitamin A/E, Vitamin C, Vitamin K1, as well as Vitamins B1, B2, and B6.

With millions of tests performed annually, 25-OH Vitamin D remains one of the fastest growing assays in the US. This new assay offered by Eagle is unique because it offers 100% cross reactivity with both major isomers of Vitamin D: Vitamin D2 and Vitamin D3 as well as offering outstanding sensitivity to 1.9 ng/mL.

“We are thrilled to be offering this 25-Hydroxy Vitamin D ELISA to the US market. We now can offer researchers a tool that can provide results in less than 3 hours using a simple ELISA format while still maintaining the most competitive pricing in the industry.” said Dan Keefe, President at Eagle. He continued,”Most 25-OH Vitamin D assays are either geared toward the high-throughput users or are strictly research assays that require extraordinary conditions like long incubation times or a 37°C incubation. Our new 25-OH Vitamin D ELISA blends the usability and convenience of clinical assays with the pricing and sensitivity of a research assay.”

Eagle anticipates offering promotional pricing in the coming months for researchers measuring 25-OH Vitamin D. These assay kits are currently for research use only. Check out the Eagle website www.EagleBio.com or call 866-411-8023 for full details.

Eagle Biosciences announces the product launch of 4 new catecholamine assays kits designed for serum, plasma, tissue, and other biological samples. The 4 ELISA kits include Noradrenaline Ultrasensitive ELISA Assay Kit which allows for sample size as low as 20 µl, Adrenaline Ultrasensitive ELISA Assay Kit with a sensitivity of 1.6 pg/ml , Dopamine Ultrasensitive ELISA Assay Kit with a sensitivity of 5.9 pg/ml , and Noradrenaline / Dopamine Combination Ultrasensitive ELISA Assay Kit which is intended for the quantitative determination of both Noradrenaline as well as Dopamine in all types of biological samples on 2 different 96-well microplates.

Developed and manufactured by DLD Diagnostika in Germany (www.DLD-Diagnostika.de), these new assays offer researchers new tools to measure catecholamines on various types of samples including serum, plasma, urine, tissue, cell culture, as well as many other types of biological samples. Each kit has an extraction plate and reagent set included to allow for great flexibility with sample types while still maintaining outstanding sensitivity.

“Eagle is quite energized to now offer these new catecholamine assay kits from DLD Diagnostika”, said Dan Keefe, President of Eagle Biosciences. “These are the most sensitive assays in the world for Adrenaline, Noradrenaline, and Dopamine. And with the included extraction plate and reagents, many different species samples like mouse, rat, and canine can be measured with these ELISA kits as well. This is great news for researchers.”

Eagle is offering promotional pricing for researchers measuring Noradrenaline, Dopamine, and Adrenaline through July 2012. These assay kits are currently for research use only. Check out the Eagle website www.EagleBio.com or call 866-411-8023 for full details.

Binzwangen, Germany: ibt – immunological and biochemical testsystems GmbH signs Eagle Biosciences, Inc. as their exclusive distributor of the research use biotinylated IGF’s and analogs, biotinylated IGFBP’s, Western-ligand blotting and ELISA Kits for the North American market.

ibt – immunological and biochemical testsystems GmbH (ibt) focuses on the development of antibodies and immunoassay kits for Insulin-like Growth Factors (IGF’s), Insulin-like Growth Factor Binding Proteins (IGFBP’s) and related molecules. ibt’s new biotinylation technology ensures full biological activity of the molecules. Applications of biotinylated IGF´s and other peptides and proteins are in western-ligand blotting, ELISA assay kits, protease assays, IHC, immunoprecipitation, cross-linking, cell sorting, immunohistochemistry, receptor binding and internalization studies and experimental cell therapy and tissue regeneration. Eagle Biosciences is a premier supplier of unique and quality research and clinically relevant laboratory products.

“ibt is a very well established diagnostic company with a reputation of developing high quality products.” states Dan Keefe, president of Eagle Biosciences. “ibt has a unique product line and they have enjoyed great success with researchers in Europe. They provide fantastic tools for measuring insulin, IGF-1 and IGFBP’s. In addition, they developed an assay for SDF-1 Alpha (CXCL 12) as well as assays for total and bioactive IGFBP-3 and IGFBP-4 in serum, plasma, or biological fluids. We are very proud to promote the ibt product line in the US and Canada. “

Eagle is offering promotional pricing for researchers measuring IGFBP-3 and IGFBP-4 through the end of September 2012. These assay kits are currently for research use only. Check out the Eagle website www.EagleBio.com or call 866-411-8023 for full details.