Corporate Banner
Satellite Banner
Technology
Networks
Scientific Communities
 
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 2,400+ scientific posters on ePosters
  • More Than 3,700+ 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

High-Resolution 3D Images Reveal the Muscle Mitochondrial Power Grid
NIH mouse study overturns scientific ideas on energy distribution in muscle.
Friday, July 31, 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
Young South African Women can Adhere to Daily PrEP Regimen as HIV Prevention
NIH-funded study finds men in Bangkok, Harlem also successful in taking daily dose.
Saturday, July 25, 2015
Study Shows Promise of Precision Medicine for Most Common Type of Lymphoma
The study appeared online July 20, 2015, in Nature Medicine.
Tuesday, July 21, 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
NIH Study Identifies Gene Variant Linked to Compulsive Drinking
Mice carrying the Met68BDNF gene variant would consume excessive amounts of alcohol.
Tuesday, July 21, 2015
HIV Control Through Treatment Durably Prevents Heterosexual Transmission of Virus
NIH-funded trial proves suppressive antiretroviral therapy for HIV-infected people effective in protecting uninfected partners.
Tuesday, July 21, 2015
Early Antiretroviral Therapy Prevents Non-AIDS Outcomes in HIV-infected People
NIH-supported findings illustrate manifold benefit of therapy.
Tuesday, July 21, 2015
Futuristic Brain Probe Allows for Wireless Control of Neurons
NIH-funded scientists developed an ultra-thin, minimally invasive device for controlling brain cells with drugs and light.
Saturday, July 18, 2015
House Votes in Favor of Bill Boosting NIH Funding
The US House of Representatives today overwhelmingly voted in favor of a bill that would increase funding to the NIH by about $10 billion, help speed the development of new drugs, and advance precision medicine initiatives.
Monday, July 13, 2015
NIH-funded Vaccine for West Nile Virus Enters Human Clinical Trials
Enrollment is expected to be completed by December 2015.
Tuesday, July 07, 2015
In Blinding Eye Disease, Trash-Collecting Cells Go Awry, Accelerate Damage
NIH research points to microglia as potential therapeutic target in retinitis pigmentosa.
Friday, July 03, 2015
Boys More Likely to Have Antipsychotics Prescribed, Regardless of Age
NIH-funded study is the first look at antipsychotic prescriptions patterns in the U.S.
Thursday, July 02, 2015
Potential Therapeutic for Blinding Eye Disease
NIH research points to microglia as potential therapeutic target in retinitis pigmentosa.
Thursday, July 02, 2015
New Medication for Alcohol Use Disorder
NIH begins clinical trial investigating a potential treatment for alcohol use disorder.
Friday, June 26, 2015
Scientific News
Study Finds Brain Chemicals that Keep Wakefulness in Check
Researchers to develop new drugs that promote better sleep, or control hyperactivity in people with mania.
Sorting Through Cellular Statistics
Aaron Dinner, professor in chemistry, and his graduate student Herman Gudjonson are trying to read the manual of life, DNA, as part of the Dinner group’s research into bioinformatics—the application of statistics to biological research.
Playing 'Tag' with Pollution lets Scientists See Who's It
Using a climate model that can tag sources of soot from different global regions and can track where it lands on the Tibetan Plateau, researchers have determined which areas around the plateau contribute the most soot — and where.
Women’s Immune System Genes Operate Differently from Men’s
A new technology reveals that immune system genes switch on and off differently in women and men, and the source of that variation is not primarily in the DNA.
Long Telomeres Associated with Increased Lung Cancer Risk
Genetic predisposition for long telomeres predicts increased lung adenocarcinoma risk.
First Artificial Ribosome Designed
Researchers at the University of Illinois at Chicago and Northwestern University have engineered a tethered ribosome that works nearly as well as the authentic cellular component, or organelle, that produces all the proteins and enzymes within the cell.
High-Resolution 3D Images Reveal the Muscle Mitochondrial Power Grid
NIH mouse study overturns scientific ideas on energy distribution in muscle.
Expanding the Brain
A team of researchers has identified more than 40 new “imprinted” genes, in which either the maternal or paternal copy of a gene is expressed while the other is silenced.
Identifying a Key Growth Factor in Cell Proliferation
Researchers discover that aspartate is a limiter of cell proliferation.
Study Uncovers Target for Preventing Huntington’s Disease
Scientists from Cardiff University believe that a treatment to prevent or delay the symptoms of Huntington’s disease could now be much closer, following a major breakthrough.
Scroll Up
Scroll Down
Skyscraper Banner

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
2,400+ scientific and medical posters
A library of 2,500+ scientific videos on LabTube
3,700+ scientific videos
Close
Premium CrownJOIN TECHNOLOGY NETWORKS PREMIUM FREE!