New Hope For An Amd Treatment
L-DOPA is available worldwide and goes by the generic name of levodopa. Brand names include Sinemet, Parcopa, Atamet, Stalevo, Madopar, and Prolopa.
Despite persistent, dedicated work by scientists, it has been longer than a decade since a new type of drug was developed for AMD, and scientists still do not understand precisely what causes it. AMD remains a chief cause of legal blindness in adults over age 60. While leaving peripheral sight intact , it destroys the center. The resulting black hole makes people unable to drive, read, recognize faces and perform daily tasks.
The only measures currently available to stall and sometimes prevent AMD are the AREDS-proven vitamins for early AMD, and scheduled eye injections for the neovascular form, known as wet AMD.
Guiding Students Toward The Future
Figueroa began working in the McKay Lab as an undergraduate in the summer of 2016 and continues to work there as a research technician, after graduating with a bachelors degree in neuroscience and cognitive science and a minor in physiology and anthropology. After completing two research papers, she plans to turn her attention to medical school applications.
All my students have different paths. My path is to help them get to where theyre going.Brian S. McKay, PhD
Dr. McKay trains high-school to graduate students in laboratory research methods and the concepts behind experimental design as they help him research treatment and prevention of AMD and glaucoma.
My goal is to figure out where the students want to go and help them get there, says Dr. McKay. All my students have different paths. My path is to help them get to where theyre going.
Dr. McKays students follow these paths to a wide range of destinations.
Different students have different goals. In the end, its their life and their decisions, Dr. McKay says. One just graduated from optometry school, one decided shes going to do psychiatry, one is a practicing ophthalmologist in Phoenix, for example.
Shows Power Of Big Data
Big data research methods use customized computer programs to search through millions of electronic medical records and analyze their contents. This research method helped compare the analysis of the 37,000 Marshfield files with an exponentially larger pool of 87 million medical records. This big data exercise confirmed the research teams initial conclusions.
The next stage for the research team is to launch a clinical trial to further test the ability of L-DOPA to slow or prevent AMD. Continued success of this hypothesis could lead to a new and life-changing example of what is known as drug repurposing or repositioning, in which scientists identify new uses for existing drugs.
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Can A Parkinson’s Drug Treat Macular Degeneration
By Serena McNiff HealthDay Reporter
WEDNESDAY, Sept. 16, 2020 — A drug long used to treat Parkinson’s disease may benefit patients with a severe form of age-related macular degeneration , a small clinical trial suggests.
One of the leading causes of vision loss in older people is a condition called dry macular degeneration. More than 15% of Americans over age 70 have AMD, and 10% to 15% of those cases go on to develop the more severe wet macular degeneration, which can cause swift and complete vision loss.
Typically, wet AMD is treated with injections of medication into the eye. Most people need several per year to keep the disease from progressing.
But this small, early-stage clinical trial suggests an alternative may be on the horizon: the leading drug used to treat Parkinson’s disease, called levodopa.
The trial was an outgrowth of a 2016 study that found Parkinson’s patients who took levodopa were less likely to develop macular degeneration.
“The study found a relationship between taking levodopa and macular regeneration,” said Dr. Robert Snyder, a professor of ophthalmology at the University of Arizona, in Tucson. “It delayed the onset of both dry and wet macular degeneration, and reduced the odds of getting wet macular degeneration.”
Macular degeneration affects the macula, part of the eye that allows you to see fine detail. Wet AMD happens when abnormal blood vessels grow under the macula often, these blood vessels leak blood and fluid, causing rapid damage.
Visual Dysfunctions Associated With Morphological Changes In Retina
The retina, as mentioned above, consists of different neurons, dendrites, and axons, and it is responsible for integrating response to the visual system to the cortex. Clinically, patients with PD often suffer from various functional disabilities in central, peripheral, or visuoperceptual vision. Although the visual system does not exist in isolation, we focus on the retina in this article and discuss the visual disorders associated with retinal dysfunction .
Table 3. Retinal abnormalities in PD patients.
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Common Parkinsons Disease Drug May Provide Low
PHLADELPHIA Losing your vision can be a terrifying experience. One of the common causes of blindness in seniors is macular degeneration , where leaky blood vessels form under the retina. Treatments for this condition can be both painful and expensive, but a new study says there may be an unlikely solution. A drug for Parkinsons disease is showing promise in reducing the effects of AMD without creating harmful side-effects.
The report finds the drug levodopa is a safe and commonly available medication which reduces a patients need for regular AMD injections. The study continues earlier research which finds patients being treated for various movement disorders, like Parkinsons, are significantly less likely to develop macular degeneration while taking levodopa.
Levodopa has a receptor selectively expressed on pigmented cells. This receptor can be supportive of retinal health and survival, which led to the development of our hypothesis that it may prevent or treat AMD, Robert W. Snyder from the University of Arizona says in a media release.
Parkinsons Drug Eyed As Treatment For Severe Macular Degeneration
A drug long used to treat Parkinsons disease may benefit patients with a severe form of age-related macular degeneration , a small clinical trial suggests.
One of the leading causes of vision loss in older people is a condition called dry macular degeneration. More than 15% of Americans over age 70 have AMD, and 10% to 15% of those cases go on to develop the more severe wet macular degeneration, which can cause swift and complete vision loss.
Typically, wet AMD is treated with injections of medication into the eye. Most people need several per year to keep the disease from progressing.
But this small, early-stage clinical trial suggests an alternative may be on the horizon: the leading drug used to treat Parkinsons disease, called levodopa.
The trial was an outgrowth of a 2016 study that found Parkinsons patients who took levodopa were less likely to develop macular degeneration.
The study found a relationship between taking levodopa and macular regeneration, said Dr. Robert Snyder, a professor of ophthalmology at the University of Arizona, in Tucson. It delayed the onset of both dry and wet macular degeneration, and reduced the odds of getting wet macular degeneration.
Macular degeneration affects the macula, part of the eye that allows you to see fine detail. Wet AMD happens when abnormal blood vessels grow under the macula often, these blood vessels leak blood and fluid, causing rapid damage.
More information
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Retinal Ganglion Cells Loss And Retinal Nerve Fiber Layer Thinning
As previously mentioned, the ophthalmological examinations visualize on the surface of the retina, such as the RNFL and the retinal capillaries . Though it is not certain that all retinal thinning in PD is due to a-Syn aggregation or dopaminergic neuronal loss, the two main pathological hallmarks may damage retina structure , interfere with signal transmission, and hence cause visual dysfunction.
Most non-invasive study of the retina in PD patients concentrated on the correlation of thinning RNFL detected by OCT. Inzelberg et al. first assessed with OCT and reported the RNFL thinning in patients with PD compared with controls. The results showed a decrease in the thickness of inferior quadrant RNFL near its entry to the optic nerve head . Since then, it has been identified that the RNFL thickness was significantly thinner in four different quadrants, ranging superior, temporal , inferior , and nasal in the retina of participants with PD. Likewise, the RNFL thickness in the macular region of PD was significantly lower than in the control groups . Notably, the OCT quantification in macular seems to have a higher diagnostic yield than RNFL quadrants quantification . Sparkly, most studies revealed a significant thinning of the RNFL in the IRL and in the central 5-mm quadrant of the macula , while no significant changes in the ORL of the retina .
Strengths And Limitations Of This Study
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This study includes a complete assessment of visual function parameters and the evaluation of different retinal structures using spectral domain optical coherence tomography in patients with Parkinson’s disease.
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There are only two other published articles evaluating the association between visual dysfunction and morphological parameters. Results provided by these previous studies differ from our results, possibly due to different measurement methods and sample size.
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Colour vision in our study was assessed by Lanthony and Farnsworth D15 colour tests, which may provide more specific information about colour deficiencies. These tests are not commonly used to evaluate colour deficiencies in patients with PD.
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An important limitation to our study is the inclusion of one randomly selected eye per patient. The incorporation of both eyes of each patient in Parkinson’s disease studies is usually recommended due to asymmetrical involvement of the retina in this process.
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Study Suggests Further Research Is Needed To Compare The Association During Long
| Patients with AMD may be at increased risk for Parkinson’s disease. |
Age-related macular degeneration shares some risk factors with Parkinsons disease , and studies have reported a higher tendency for AMD patients to have PD. A recent study aimed to further evaluate this relationship and investigate the risk of PD among patients with AMD, as well as its association with confounding comorbidities.
A population-based retrospective cohort study was conducted, and AMD and non-AMD cohorts were established to determine the diagnosis of PD. A total of 20,848 patients were enrolled, half of which were AMD patients and the other half were controls. The follow-up period was from the index date of AMD diagnosis to the diagnosis of PD, death or withdrawal from the program.
During the analysis of AMD subtypes , there was no significant difference in risk of PD.
The non-significant difference of PD risk between non-neovascular and neovascular may need further research stratified by the diseases stage since it does not define the stage of AMD by the ICD-9-CM codes as non-neovascular or neovascular AMD, the authors explained. The follow-up time in our study started from when AMD was diagnosed rather than the true duration of the disease, which might be even longer than the time we recorded. Perhaps the duration or the stage of the AMD might be associated with different degrees of the risk of PD.
Levodopa May Improve Vision In Patients With Macular Degeneration
- Date:
- Elsevier
- Summary:
- Investigators have determined that treating patients with an advanced form of age-related macular degeneration with levodopa, a safe and readily available drug commonly used to treat Parkinson’s disease, stabilized and improved their vision. It reduced the number of treatments necessary to maintain vision, and as such, will potentially reduce the burden of treating the disease, financially and otherwise.
Investigators have determined that treating patients with an advanced form of age-related macular degeneration with levodopa, a safe and readily available drug commonly used to treat Parkinson’s disease, stabilized and improved their vision. It reduced the number of treatments necessary to maintain vision, and as such, will potentially reduce the burden of treating the disease, financially and otherwise. Their findings appear in the American Journal of Medicine, published by Elsevier.
Earlier research found that patients being treated with levodopa for movement disorders such as Parkinson’s disease were significantly less likely to develop any type of AMD. Lead investigator Robert W. Snyder, MD, PhD, Department of Biomedical Engineering, The University of Arizona, Tucson, and Snyder Biomedical Corporation, Tucson, AZ, USA, explained, “Levodopa has a receptor selectively expressed on pigmented cells. This receptor can be supportive of retinal health and survival, which led to the development of our hypothesis that it may prevent or treat AMD.”
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Parkinson’s Drug May Help Macular Degeneration
But more research needed to confirm beneficial effects on vision disorder
HealthDay Reporter
THURSDAY, Nov. 12, 2015 — A common Parkinson’s disease medication might hold potential for preventing or treating macular degeneration, the leading cause of vision loss in the elderly, new research suggests.
At this stage, no one is recommending that patients take the drug, levodopa , to thwart eye disease. But the findings are intriguing, researchers said.
“Patients taking L-dopa for any reason are much less likely to develop age-related macular degeneration. If they do, they develop the disease much later in life than those not taking L-dopa,” said study lead author Brian McKay, an associate professor of ophthalmology and vision science at the University of Arizona.
However, the study doesn’t actually prove that levodopa causes a lower incidence of age-related macular degeneration. It only uncovered an association between the two.
Age-related macular degeneration affects about 30 percent of those older than 75, McKay said. It is caused by deterioration of the macula, the center part of the retina, and by affecting vision, it can severely limit the ability to perform everyday activities. Treatments can slow its progression but there is no cure, and it can lead to blindness.
The researchers found that diagnosis of age-related macular degeneration occurred, in general, around age 71. But among those who took levodopa, it occurred much later, at around age 79.
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Morphological And Functional Technologies In The Retina
As the eye is an extension of the brain, the retina displays similarities to the brain in anatomy, functionality, and pathological responses to environmental insult. So, to detect retinal morphological parameters of brain pathologies using imaging techniques seems reasonable.
Figure 2. The brief historical timeline marking events elucidating morphological and technologies in the retina. These new, cost-effective, high-resolution imaging tools enabled increases in imaging speeds and quantity, further catering to the clinical needs of diagnosis and therapeutics of diseases, and increasing clinical data demonstrated the important role of OCT in diagnostic and therapeutic applications of many diseases.
These techniques detect retinal nerve fiber layer thickness , central macular volumes, morphology in foveal vision , inner and outer retinal layers , and retinal pigment epithelium , and also assess retinal blood flow and vascular alterations as well as other pathological features of retina in PD patients. The monitoring retinal morphology and function are used for exploring hallmark signs corresponding to pathological conditions in different degrees and stages of PD.
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Eyes Pupils May Be Window Into Assessing Disease Stage
Prior studies have suggested that Parkinsons patients have a higher tendency for AMD. However, these failed to account for potential additional diseases, or comorbidities.
Now, researchers at the China Medical University Hospital conducted a populationbased retrospective cohort study to assess whether the risk of AMD is elevated in those with Parkinsons, taking into account comorbidities.
They reviewed data from Taiwans National Health Insurance Research Database , specifically the Longitudinal Health Insurance Database 2000 .
In total, they analyzed data from 20,848 individuals, of which 10,424 had AMD and 10,424 did not have AMD . Patients in each group were followed for a mean of 5.66 and 5.48 years, respectively. AMD and non-AMD groups were established from January 1, 2000, to December 31, 2012, to determine the diagnosis of Parkinsons.
The prevalence of comorbidities was significantly higher in the AMD group than in the non-AMD . Medication use, including statins and calcium channel blockers differed slightly between groups.
After adjusting for potential confounders, the data revealed there was a higher risk of developing Parkinsons, both for men and women, in the AMD group than in the non-AMD group.
Specifically, this risk was significantly higher in patients older than 60 and with more than one comorbidity.
AMD is associated with a higher risk of PD with adjustment for sufficient clinical comorbidities and long follow-up time, the researchers concluded.
When To Consult A Doctor
Without treatment, wet macular degeneration is to cause serious vision loss. For this reason, anyone experiencing symptoms of wet macular degeneration should seek advice from a doctor.
Earlier treatments enable doctors to slow the progression of the disease as much as possible.
For some people, the thought of having intravitreal injections may cause concerns. However, a person can ask medical professionals questions about these injections to help alleviate these concerns.
Doctors will also inform people about the potential complications of the procedure. These include:
- discomfort and pain as the anesthetic wears off
- subconjunctival hemorrhage, which refers to eye bleeding
- in rare cases, other complications, such as:
- traumatic cataract
2020 paper explains that intravitreal injections can occur in the operating room or a doctors office.
After administering the anesthesia and cleansing the eye, the medical team will ask the person to look in the direction opposite to where they intend to insert the syringe. After a brief warning, the doctor or surgeon will insert the syringe into the persons eye before injecting the VEGF inhibitors therein. The injections will only take a few moments.
The study also notes that the medical team may irrigate and lubricate the eye after the injection.
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Pathological And Morphological Changes In Retina Of Parkinsons Disease
The retina is a simple model of the brain in the sense that some pathological impairment and morphological changes from the retina may be observed or applicable to the degenerative diseases as valuable models. In the retina of PD patients, there were dopaminergic deficiency , misfolded a-synuclein , retinal ganglion cells loss , thinning of retinal nerve fiber layer , or neuroinflammatory at several levels of the visual pathway during pre-clinical stages. Moreover, studies on post-mortem of PD patients found the accumulation of misfolding -synuclein, the main culprit of the disease, in the retinal layers, especially the OPN of patients with early PD . Furthermore, evidence has indicated microvasculature changes as some potential biomarkers of retinal pathological changes in subjects with PD. Compared to the control cases using immunohistochemical staining and image analysis, Guan et al. observed the decreased capillaries branching as well as shortening length and enlarging diameter in capillary network in the substantia nigra, middle frontal cortex, and other brain stem nuclei. As van der Holst et al. described, increased risk of Parkinsonism was observed in population with cerebral small vessel disease. So these structural changes of the retina of PD have been shown the association with the progression, severity, and duration of the disease .