Breaking News
March 24, 2019 - Researchers track effects of epigenetic marks carried by sperm chromosomes
March 24, 2019 - AHA News: Family Adopts Three Children With Three Different Heart Conditions
March 24, 2019 - Research into opioid painkillers could provide clues for safer drug development
March 23, 2019 - Lung cancer survivor recounts her lifetime struggles
March 23, 2019 - Radial and femoral approach for PCI achieve similar results in terms of survival
March 23, 2019 - Study sheds light on the optimal timing of coronary angiography in NSTEMI patients
March 23, 2019 - Excess hormones could cause a condition that can lead to blindness in women, study finds
March 23, 2019 - Dramatic shifts in first-time opioid prescriptions bring hope, concern
March 23, 2019 - Antidepressant drugs may not work when neurons are out of shape
March 23, 2019 - TTUHSC El Paso to establish endowed chair in neurology through a major grant
March 23, 2019 - New device approved by FDA for treating patients with moderate-to-severe heart failure
March 23, 2019 - People with peripheral artery disease have lower Omega-3 Index, shows research
March 23, 2019 - Trigger warnings have minimal impact on how people respond to content, shows research
March 23, 2019 - Gilead Announces Data From Two Studies Supporting Further Development of GS-6207, a Novel, Investigational HIV-1 Capsid Inhibitor as a Component of Future Long-Acting HIV Therapies
March 23, 2019 - Selfish genetic elements amplify inflammation and age-related diseases
March 23, 2019 - Study provides new understanding of how the brain recovers from damage caused by stroke
March 23, 2019 - CRISPR/Cas libraries could revolutionize drug discovery
March 23, 2019 - Allergic reaction during pregnancy may alter sexual-development in offspring’s brain
March 23, 2019 - Seeing through a robot’s eyes helps those with profound motor impairments
March 23, 2019 - Recent research shows that ease of breastfeeding after C-section differs culturally
March 23, 2019 - Newly discovered parameters offer more control over efficient release of drugs
March 23, 2019 - ‘De-tabooing’ of abortion- Women would like more support from health care community
March 23, 2019 - Anti-TB drugs can increase susceptibility to Mtb reinfection
March 23, 2019 - New survey indicates need of attention to neglected tropical diseases
March 23, 2019 - Innovative in vitro method to develop easy-to-swallow medicine for children and older people
March 23, 2019 - Sugary drinks could raise risk of early deaths finds study
March 23, 2019 - Lian wins ENGINE grant for stem-cell-based therapy to treat Type 1 diabetes
March 23, 2019 - Overall, Physicians Are Happy and Enjoy Their Lives
March 23, 2019 - Researchers discover how blood vessels protect the brain during inflammation
March 23, 2019 - CDC study shows modest improvement in optimal hospital breastfeeding policy
March 23, 2019 - Family-based prevention program to reduce alcohol use among older teens
March 23, 2019 - Remote monitoring of implanted defibrillators in heart failure patients prevents hospitalizations
March 23, 2019 - Appropriate doffing of personal protective equipment may reduce healthcare worker contamination
March 23, 2019 - Window screens can suppress mosquito populations, reduce malaria in Tanzania
March 23, 2019 - Researchers discover new biomarker for postoperative liver dysfunction
March 23, 2019 - Pregnancy history may be linked to cognitive function in older women, finds study
March 23, 2019 - Study shows ticagrelor is equally safe and effective as clopidogrel after heart attack
March 23, 2019 - FDA Approves First Drug for Postpartum Depression, Zulresso (brexanolone)
March 23, 2019 - New guidelines outline new treatment management for psoriasis
March 23, 2019 - Thermally abused cooking oil may promote progression of breast cancer
March 23, 2019 - High-fructose corn syrup fuels growth of colon tumors in mice
March 23, 2019 - Partnership aims at establishing best practices to promote diversity in clinical trials
March 23, 2019 - New study examines presence of microbes in tap water from residences, office buildings
March 23, 2019 - Early life trauma may affect brain structure, contribute to major depressive disorder
March 23, 2019 - NIH starts clinical trial of drug to treat cravings associated with opioid use disorder
March 23, 2019 - Cervix bacteria, immune factors could be a warning signal of premature birth, reports new research
March 23, 2019 - Worst-ever emergency care performance figures underscore the need to focus on staffing
March 23, 2019 - The Current issue of “The view from here” is concerned with Cancer
March 23, 2019 - Mouse model validates how ‘good’ and ‘bad’ bacteria affect acne
March 23, 2019 - Individual amygdala neurons respond to touch, imagery and sounds
March 23, 2019 - Combination of two topical creams can prevent cancer
March 23, 2019 - Study suggests depression screening when assessing African-Americans for schizophrenia
March 23, 2019 - New electronic support system for choosing drug treatment based on patient’s genotype
March 23, 2019 - First-of-its-kind study provides pregnancy statistics of imprisoned U.S. women
March 23, 2019 - Marinus Pharmaceuticals Initiates Phase 3 Study in Children with PCDH19-Related Epilepsy
March 23, 2019 - Laparoscopy: MedlinePlus Lab Test Information
March 23, 2019 - Shellfish allergies: can they be treated?
March 23, 2019 - Toilet seat heart monitoring system
March 23, 2019 - Researchers identify way to improve common treatment for PTSD
March 23, 2019 - High potency cannabis use linked to psychosis finds study
March 23, 2019 - Evoke Pharma Submits Response to FDA Review Letter for Gimoti NDA
March 23, 2019 - Tracking HIV’s ever-evolving genome in effort to prioritize public health resources
March 23, 2019 - Scientists grow most sophisticated brain organoid to date
March 23, 2019 - ADHD drug raising risk of psychosis
March 22, 2019 - FDA approves brexanolone, first drug developed to treat postpartum depression
March 22, 2019 - Gruesome cat and dog experiments by the USDA exposed
March 22, 2019 - Ball pits used in children’s physical therapy may contribute to germ transmission
March 22, 2019 - Long-term use of inexpensive weight-loss drug may be safe and effective
March 22, 2019 - FDA Approves Sunosi (solriamfetol) for Excessive Daytime Sleepiness Associated with Narcolepsy or Obstructive Sleep Apnea
March 22, 2019 - Anti-Müllerian Hormone Test: MedlinePlus Lab Test Information
March 22, 2019 - Finding the right exercise, diet aids for HIV patients
March 22, 2019 - Health Plans For State Employees Use Medicare’s Hammer On Hospital Bills
March 22, 2019 - Researchers develop new tool for imaging large groups of neurons in living animals
March 22, 2019 - Certain bacteria and immune factors in vagina may cause or protect against preterm birth
March 22, 2019 - Research identifies guidelines for prioritizing hepatitis C treatment in U.S. prisons
March 22, 2019 - Novel breath test could pave new way to non-invasively measure gut health
March 22, 2019 - Pharmaceutical and personal care products may result in new contaminants in waterways
March 22, 2019 - New model could revolutionize the way researchers investigate spread of pathogens
March 22, 2019 - MSU professor receives NSF CAREER grant for biosensor diagnostics
March 22, 2019 - High-fat, high-sugar diet in mouse mothers causes problems in the hearts of offspring
New directions found in understanding, fighting glaucoma

New directions found in understanding, fighting glaucoma

image_pdfDownload PDFimage_print
Two distinctive handfuls of short molecules that regulate gene expression have been found in the eye fluid of patients with two distinct types of vision degenerating glaucoma. Pictured are Medical College of Georgia research associate and the study’s first author Michelle D. Drewry and Dr. Yutao Liu Credit: Phil Jones, Augusta University Senior Photographer

Two distinctive handfuls of short molecules that regulate gene expression have been found in the eye fluid of patients with two distinct types of vision degenerating glaucoma.

These differentially expressed microRNAs point the way toward finding more genes associated with glaucoma, more clues about how these glaucoma types each go about damaging our optic nerve and potential new points of intervention, the scientists say.

“If we know the pathways involved, maybe we can reverse this, find better targets and design better drugs,” says Dr. Yutao Liu, vision scientist and human geneticist in the Department of Cellular Biology and Anatomy at the Medical College of Georgia at Augusta University.

Currently only a handful of known genetic mutations have been found to account for about 10 percent of glaucoma, says Liu, corresponding author of the study in the journal Human Molecular Genetics.

“Differential expression” means the microRNA, or miRNA, expression could be higher or lower in the different conditions, but it’s the fact that they are significantly different that makes them of interest and potential help in better understanding and treating a leading cause of vision loss worldwide, Liu says.

The scientists examined miRNA in the aqueous humor that nourishes the front of the eye in a dozen patients with the common, primary open angle glaucoma, another dozen with the rare and even more difficult-to-treat exfoliation glaucoma, and compared the miRNA profile of each to that of 11 people with healthy eyes of a similar age.

They found expression of three miRNAs – miR-125b-5p, miR-302d-3p and miR-451a – significantly different between primary open angle glaucoma and controls. They found five – miR-122-5p, miR-3144-3p, miR-320a, miR-320e and miR-630 – markedly different between exfoliation glaucoma and controls.

Most of the miRNAs have never been associated with glaucoma. However, they do have some evidence that miR122-5p, present in exfoliation glaucoma, may target three genes, OPTN, TMCO1 and TFG-β1, already associated with glaucoma, Liu says. Their early look at the pathways of the other miRNAs they identified, shows likely glaucoma involvement with those as well.

Liu notes that each miRNA can quite literally target hundreds of genes and – in keeping with the concept of location, location, location – where they are determines which genes. Generally when miRNA expression is up, expression of impacted genes is down.

They already are exploring what these miRNA do in the trabecular meshwork that manages the continuous drainage of fluid made by the ciliary body to nourish and oxygenate a portion of the eye that has no direct blood supply.

“Now we have primary cells cultured primarily from the outflow area of the human eye, so we can take these miRNAs, synthesize them, then give them to these cells and see what kind of genes they affect and how many of those genes are related to glaucoma,” Liu says.

All of us daily lose some of the 2 million nerve fibers in our optic nerve and we can lose 50-60 percent of them without it really affecting our vision, Liu says. But glaucoma accelerates the loss and these two glaucoma types go about that damage in different ways.

In primary open angle glaucoma, pressure inside the eyeball is high because of increased fluid production, decreased excretion or both, and the optic nerve gets damaged as a result. “We think it’s a local disease in the eye,” Liu says.

The less-common and generally more severe exfoliation glaucoma occurs in people with exfoliation syndrome, which increases their chance of glaucoma about six times, according to The Glaucoma Foundation. With this glaucoma type, cells that normally secrete proteins inexplicably start to secrete more and the proteins cluster, forming structures that are too big to pass through the eye’s normal fluid outflow pathway.

Liu has evidence that a crosslinking enzyme, also secreted at high levels in these patients, effectively glues together these pieces that resemble dandruff. Collateral damage apparently also occurs in the colored-part of the eye, the iris, as pigment also starts to slough off, adding to the mounting pile of trash in the eye. This form of glaucoma is all about high pressure and traditional eye drops won’t help, Liu notes. Outflow pathways reopened by surgery quickly become blocked again. Liu notes that this abnormal protein secretion occurs in other parts of the body as well with exfoliation syndrome, but appears to be problematic only in the eye.

Using eye drops that improve outflow or decrease fluid production can reduce the risk of eye damage in most patients with more common types of glaucoma, Liu says. Patients often need a combination of drops that have to be taken several times daily. Surgery or laser treatment can also increase outflow. But Liu and his colleagues would like to find more targeted and effective options.

The eye’s aqueous humor also helps support the eye’s shape and enables waste removal. The fluid comes from the general circulation and gets dumped back into it. That means that high blood pressure in the body also can impact eye pressure and that exercise can help reduce eye pressure, Liu adds. In fact, eye pressure can even be reactive like blood pressure: Liu notes that his goes up when he wears a tie. Our intraocular pressure tends to be highest in the morning and lowest when we are lying down and sleeping.


Explore further:
Study finds genetic link between thinner corneas and increased risk of glaucoma

Journal reference:
Human Molecular Genetics

Provided by:
Medical College of Georgia at Augusta University

Tagged with:

About author

Related Articles