Corporate Banner
Satellite Banner
Biomolecular Screening
Scientific Community
 
Become a Member | Sign in
Home>News>This Article
  News
Return

Therapy May Curb Kidney Deterioration in Patients with Rare Disorder

Published: Tuesday, July 30, 2013
Last Updated: Tuesday, July 30, 2013
Bookmark and Share
Innovation in mouse model helps researchers distinguish disease mechanisms and biomarkers.

A team led by researchers at the National Institutes of Health has overcome a major biological hurdle in an effort to find improved treatments for patients with a rare disease called methylmalonic acidemia (MMA). Using genetically engineered mice created for their studies, the team identified a set of biomarkers of kidney damage -- a hallmark of the disorder -- and demonstrated that antioxidant therapy protected kidney function in the mice. 

Researchers at the National Human Genome Research Institute (NHGRI), part of NIH, validated the same biomarkers in 46 patients with MMA seen at the NIH Clinical Center. The biomarkers offer new tools for monitoring disease progression and the effects of therapies, both of which will be valuable in the researchers' design of clinical trials for this disease.

The discovery, reported in the July 29, 2013, advance online issue of the Proceedings of the National Academy of Sciences, paves the way for use of antioxidant therapy in a clinical trial for patients with MMA. It also illustrates the mechanisms by which dysfunction of mitochondria -- the power generators of the cell -- affects kidney disease. Mitochondrial dysfunction is a factor not only in rare disorders, such as MMA, but also in a wide variety of common conditions, such as obesity, diabetes and cancer.

MMA affects as many as one in 67,000 children born in the United States. It can have several different causes, all involving loss of function of a metabolic pathway that moderates levels of an organic compound called methylmalonic acid. Affected children are unable to properly metabolize certain amino acids consumed in their diet, which damages a number of organs, most notably the kidneys. 

"Metabolic disorders like MMA are extremely difficult to manage because they perturb the delicate balance of chemicals that our bodies need to sustain health," said Daniel Kastner, M.D., Ph.D., NHGRI scientific director. "Given that every newborn in the United States is screened for a number of inherited metabolic disorders, including MMA, there is a critical need for better understanding of the disease mechanisms and therapies to treat them."

MMA is the most common organic acid disorder and invariably impairs kidney function, which can lead to kidney failure. The most common therapy is a restrictive diet, but doctors must resort to dialysis or kidney transplantation when the disease progresses. MMA patients also suffer from severe metabolic instability, failure to thrive, intellectual and physical disabilities, pancreatitis, anemia, seizures, vision loss and strokes.

"There are no definitive treatments for the management of patients with MMA," said Charles Venditti, M.D., Ph.D., senior author and investigator in the Organic Acid Research Section of NHGRI's Genetics and Molecular Biology Branch. "This study is the culmination of collaboration with the patient community. It uses mouse modelling, coupled with innovations in genomics and biochemical analyses, to derive new insights into the causes of renal injury in MMA. Our studies have improved our understanding of the basic biology underlying MMA, created a novel animal model for testing interventions and, now, led us to the promise of a new therapy."  

The researchers performed the studies using mice bred to carry gene alterations that disrupt the production of the same mitochondrial enzyme that is defective in patients with MMA. These are called transgenic mice. The enzyme, called methylmalonyl-CoA mutase (MUT), is an important component of the chemical process that metabolizes organic acids, specifically methylmalonic acid. 

By measuring gene expression in the transgenic mice using DNA microarrays, researchers discovered 50 biomarkers of gene expression that each indicated declining kidney function. DNA microarrays are silicon chips with many spots to which a given molecule may bind. In this case, the DNA microarrays were used to precisely generate, with the aid of a computer program, a profile of gene expression in a kidney cell.

The researchers chose one of the biomarkers, called lipocalin-2, to test how it correlated with kidney function in 46 MMA patients. Plasma levels of this biomarker rose with kidney deterioration in patients with MMA, and may serve as a valuable indicator of MMA kidney disease progression in the clinic.

"The detection of biomarkers through microarray technology is immensely helpful in pointing to downstream pathways affected by the defective MUT activity," said Irini Manoli, M.D., Ph.D., lead author and a physician scientist and staff clinician in NHGRI's Genetics and Molecular Biology Branch. "The biomarkers provide new plasma or serum tests to follow disease progression in our patients." 

Having discovered these important biomarkers of kidney function, the authors turned to kidney physiology experts on their team to explore the structural changes that occur in MMA disease. They analyzed the rate at which the kidneys filter waste from the blood. Co-author and renal physiology expert Jurgen Schnermann, M.D., and members of his laboratory at the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), also part of NIH, demonstrated the early and significant decrease in this rate in MMA mice. 

With further studies, the researchers identified increased production of free radicals in tissues from the mice, as well as in the MMA patients. Detection of free radicals indicates chemical instability in cells, which the researchers sought to remedy with antioxidant therapy. After treating the mice with two forms of dietary antioxidants, the researchers observed that the biomarkers of kidney damage diminished and the faltering kidney filtration rate tapered off. The findings demonstrated that readily available antioxidants can significantly affect the rate of decline of kidney function in transgenic mice, which replicate the kidney disease of MMA.

"The next step will be to translate these findings to the clinic," Dr. Venditti said. "With a progressive disorder like MMA, we are hopeful that we have achieved a laboratory success that our patients will benefit from in the near future."


Further Information
Access to this exclusive content is for Technology Networks Premium members only.

Join Technology Networks Premium for free access to:

  • Exclusive articles
  • Presentations from international conferences
  • Over 2,500+ scientific posters on ePosters
  • More than 3,800+ scientific videos on LabTube
  • 35 community eNewsletters


Sign In



Forgotten your details? Click Here
If you are not a member you can join here

*Please note: By logging into TechnologyNetworks.com you agree to accept the use of cookies. To find out more about the cookies we use and how to delete them, see our privacy policy.

Related Content

Tell-tale Biomarker Detects Early Breast Cancer in NIH-funded Study
The study published online in the issue of Nature Communications.
Thursday, August 13, 2015
Protein Related to Long Term Traumatic Brain Injury Complications Discovered
NIH-study shows protein found at higher levels in military members who have suffered multiple TBIs.
Tuesday, August 04, 2015
Crystal Clear Images Uncover Secrets of Hormone Receptors
NIH researchers gain better understanding of how neuropeptide hormones trigger chemical reactions in cells.
Monday, August 03, 2015
Vital Protein in Healthy Fertilization Process Identified
Researchers at the National Institutes of Health have discovered a protein that plays a vital role in healthy egg-sperm union in mice.
Monday, July 27, 2015
NIH Joins Public-Private Partnership to Fund Research on Autism Biomarkers
Biomarkers Consortium project to improve tools for measuring and treating social impairment in children with autism.
Tuesday, July 21, 2015
Potential Therapeutic for Blinding Eye Disease
NIH research points to microglia as potential therapeutic target in retinitis pigmentosa.
Thursday, July 02, 2015
Linking Targeted Cancer Drugs to Gene Abnormalities
Investigators at the NIH have announced a series of clinical trials that will study drugs or drug combinations that target specific genetic mutations.
Wednesday, June 03, 2015
Possible Treatment for Lethal Pediatric Brain Cancer
NIH-funded preclinical study suggests epigenetic drugs may be used to treat leading cause of pediatric brain cancer death.
Tuesday, May 05, 2015
HIV can Spread Early, Evolve in Patients' Brains
Findings add urgency to screening, treatment - NIH-funded study.
Saturday, March 28, 2015
Test Reliably Detects Inherited Immune Deficiency in Newborns
NIH-supported study suggests that early diagnosis of severe combined immunodeficiency leads to high survival rates.
Thursday, August 21, 2014
NIH Names New Clinical Sites in Undiagnosed Diseases Network
Four-year, $43 million initiative engages broad expertise in study of mystery conditions.
Wednesday, July 02, 2014
Underlying Genetics and Marker For Stroke Discovered
NIH-funded findings point to new potential strategies for disease prevention, treatment.
Friday, March 21, 2014
Epigenetic Clock Marks Age of Human Tissues and Cells
The age of many human tissues and cells is reflected in chemical changes to DNA. The finding provides insights for cancer, aging, and stem cell research.
Tuesday, November 05, 2013
Brain May Flush Out Toxins During Sleep
NIH-funded study suggests sleep clears brain of damaging molecules associated with neurodegeneration.
Friday, October 18, 2013
NIH Researchers Identify Candidate Drug to Treat Batten Disease
The drug, tested in mice, was found to slow the loss of coordination seen in the disorder extending the animals’ life span.
Tuesday, October 01, 2013
Scientific News
Promising Class of New Cancer Drugs Cause Memory Loss in Mice
New findings from The Rockefeller University suggest that the original version of BET inhibitors causes molecular changes in mouse neurons, and can lead to memory loss in mice that receive it.
Electrical Control of Cancer Cells
Research led by scientists at The University of Texas Health Science Center at Houston (UTHealth) has revealed a new electrical mechanism that can control these switches.
Signature of Microbiomes Linked to Schizophrenia
Studying microbiomes in throat may help identify causes and treatments of brain disorder.
Inflammation Linked to Colon Cancer Metastasis
A new Arizona State University research study led by Biodesign Institute executive director Raymond DuBois has identified for the first time the details of how inflammation triggers colon cancer cells to spread to other organs, or metastasize.
Structural Discoveries Could Aid in Better Drug Design
Scientists have uncovered the structural details of how some proteins interact to turn two different signals into a single integrated output.
Determining the Age of Fingerprints
Watch the imprint of a tire track in soft mud, and it will slowly blur, the ridges of the pattern gradually flowing into the valleys. Researchers have tested the theory that a similar effect could be used to give forensic scientists a way to date fingerprints.
Genetic Overlapping in Multiple Autoimmune Diseases May Suggest Common Therapies
CHOP genomics expert leads analysis of genetic architecture, with eye on repurposing existing drugs.
Surprising Mechanism Behind Antibiotic-Resistant Bacteria Uncovered
Now, scientists at TSRI have discovered that the important human pathogen Staphylococcus aureus, develops resistance to this drug by “switching on” a previously uncharacterized set of genes.
Tissue Bank Pays Dividends for Brain Cancer Research
Checking what’s in the bank – the Brisbane Breast Bank, that is – has paid dividends for UQ cancer researchers.
Researchers Publish Landmark “Basket Study”
Researchers from Memorial Sloan Kettering Cancer Center (MSK) have announced results from the first published basket study, a new form of clinical trial design that explores responses to drugs based on the specific mutations in patients’ tumors rather than where their cancer originated.
SELECTBIO

Skyscraper Banner
Go to LabTube
Go to eposters
 
Access to the latest scientific news
Exclusive articles
Upload and share your posters on ePosters
Latest presentations and webinars
View a library of 1,800+ scientific and medical posters
2,500+ scientific and medical posters
A library of 2,500+ scientific videos on LabTube
3,800+ scientific videos
Close
Premium CrownJOIN TECHNOLOGY NETWORKS PREMIUM FREE!