Looking Beyond a Disease: Unraveling Huntington’s Disease Through Research
The patients who see Natalia Pessoa Rocha, PhD, a postdoctoral research fellow in the laboratory of Antonio L. Teixeira, MD, PhD, carry a heavier burden than most. Some come in wheelchairs, bereft of muscle control in their legs. Others seem the perfect picture of health. But one tie binds them inextricably together: Huntington’s disease.
“Every day, I am met with a different story, a very beautiful story that tells much more about them than the disease itself,” Rocha says. “I don’t call them Huntington’s disease patients because they cannot be defined by this disease. They are much more than that.”
A fatal, incurable genetic disorder that breaks down nerve cells in the brain, Huntington’s disease usually appears in a person’s 30s or 40s, gradually impairing mental and physical functions. Patients suffer loss of movement control; cognitive decline; and psychiatric symptoms such as anxiety, mania, and depression. Treatment can help relieve symptoms, but doctors remain powerless to slow the disease itself. It leaves late-stage patients bedridden, unable to speak, and wholly dependent on others for care.
Huntington’s disease stems from an inherited gene defect; parents have a 50 percent chance of passing it to their children, and testing can identify if a person has the defective gene before symptoms appear.
“Every time I talk to a patient, they say, ‘Please help us. Please find a cure,’” Rocha says. “They’ve seen parents and other family members with Huntington’s disease, so they know what will come.”
Giving hope to Huntington’s disease through research
To deliver on this plea, Rocha works to discover the link between Huntington’s disease and the immune system. Scientists know that inflammation—the body’s response to perceived harm—interacts with neurodegenerative diseases such as Parkinson’s disease and Alzheimer’s disease, which Rocha studied in her native Brazil. But the effects of this interaction and how it might relate to Huntington’s disease remain murky.
“There is a time point with neurodegenerative diseases—we don’t know exactly when this time point occurs—when instead of helping, the immune system can contribute to neuron damage,” Teixeira says.
Rocha evaluates patients at the Huntington’s Disease Society of America Center of Excellence at McGovern Medical School at UTHealth. Directed by Erin Furr Stimming, MD, the center is the only one of its kind in Texas, drawing patients from across the country to receive comprehensive care and participate in research.
Teixeira’s team conducts a comprehensive clinical evaluation of physical, psychological, and cognitive symptoms. They also draw blood samples to test for inflammatory markers that might relate to changes in clinical symptoms. Rocha says entire families will come to help with research, including young patients who carry the Huntington’s gene and want to believe that their futures are not already written.
“When they look at me, I see hope in their eyes,” she says.
A neurodegenerative disease with behavioral health implications
For others, hope seems hard to come by. Roughly half of patients with Huntington’s suffer from depression, which scientists believe results mostly from changes the disease causes in the brain rather than the psychological impact of a Huntington’s diagnosis.
Gabriela Colpo, PhD, also a research fellow in Teixeira’s lab, focuses her work on this aspect of Huntington’s disease. When Rocha tests patients, Colpo evaluates them to determine why some develop depression and others do not. She is searching for genetic pathways that might lead to depression in her patients.
“Depression usually starts much earlier than movement symptoms,” Colpo says.
Research gives hope that the days of Huntington’s disease as an unstoppable force may be ending. New therapies like stem cells are showing promise in early research—Colpo is preparing a preclinical trial to see if stem cells can improve symptoms or delay the onset of the disease itself.
“I am amazed at how hard they are trying with all the difficulties associated with the disease,” Rocha says. “If they are trying that hard, I think we have to try even harder.”
As Rocha continues her research, she says the patients she sees help her more than she helps them; they inspire her with their determination—even during the late, debilitating stage of Huntington’s—to fight to their utmost ability.
Written by: John Evans