Parkinson Disease

Parkinson’s disease is a progressive neurological condition that affects movement and can also affect speech, sleep, mood, thinking, digestion, and blood-pressure control. It is linked to the gradual loss of dopamine-producing nerve cells in a part of the brain called the substantia nigra. Dopamine helps coordinate smooth, purposeful movement. Symptoms and the pace of change vary from person to person. A neurologist, ideally one with experience in movement disorders, can help confirm the diagnosis, tailor treatment, and monitor changes over time.

Common Symptoms

There is no cure for Parkinson’s disease, but established treatment can meaningfully improve symptoms, function, and quality of life. Care is individualized and often combines medication, regular exercise, rehabilitation, and treatment of nonmotor symptoms.

Common Treatment Options

• Medication: Levodopa and other medicines can improve movement symptoms. Medication choices and timing are adjusted over time.
• Physical, occupational, and speech therapy: These services can support mobility, daily function, communication, swallowing, and safety.
• Exercise: Regular, appropriately tailored exercise is an important part of Parkinson’s care.
• Deep brain stimulation: Some people whose symptoms are not adequately managed with medication may be evaluated for this surgical option.
• Supportive care: Sleep, mood, constipation, pain, and cognitive symptoms should be assessed and treated as part of the overall care plan.

Stem cell therapy for Parkinson’s disease is an area of emerging research. Scientists are studying more than one cell-based approach, including cell replacement and mesenchymal stromal cell, or MSC, therapies.

What Researchers Are Studying

• Replace dopamine-producing cell precursors through specialized surgical procedures
• Influence inflammatory signaling and other biological processes
• Be delivered safely and feasibly in carefully selected patients
• Be further evaluated for their effects on motor symptoms, daily function, and quality of life

Cell replacement uses laboratory-grown dopamine-cell precursors transplanted into the brain. MSC research examines a different strategy, often focused on possible effects on inflammation and signaling. These approaches are not interchangeable.

Note: Stem cell therapies for Parkinson’s disease are not FDA-approved and are investigational. Research findings do not guarantee individual results.

How Stem Cell Therapy for Parkinson’s Disease Is Being Studied

Cell-replacement studies examine whether transplanted dopamine-cell precursors can survive, function biologically, and be delivered safely in carefully selected participants. MSC studies examine safety, feasibility, and possible changes in motor scores. Researchers are evaluating different cell products, doses, delivery methods, and outcomes to help guide continued clinical research. Stem cell treatment for Parkinson’s disease remains investigational.

2025: Embryonic Stem Cell-Derived Dopamine Neurons Reported Graft Survival and Motor Improvements

Phase I Trial of hES Cell-Derived Dopaminergic Neurons for Parkinson’s Disease — Read Study

This phase I study enrolled 12 people with Parkinson’s disease who received a surgical transplant of bemdaneprocel, a dopamine-neuron progenitor product derived from human embryonic stem cells, into both sides of the putamen. Five participants received a lower dose, and seven received a higher dose. All participants received one year of immunosuppressive medication. At 18 months, the investigators reported no cell-product-related serious adverse events, and imaging findings were consistent with graft survival. Motor scores improved in some participants, particularly in the higher-dose group. These findings add to clinical research on dopamine-neuron replacement for Parkinson’s disease.

2025: Repeated Allogeneic MSC Infusions Reported Motor Improvements and Mild Adverse Events

Allogeneic Bone Marrow-Derived Mesenchymal Stem Cells for Parkinson’s Disease: A Randomized Trial — Read Study

This single-center phase II randomized, placebo-controlled trial enrolled 45 people with mild-to-moderate Parkinson’s disease. Participants received three MSC infusions, one placebo infusion followed by two MSC infusions, or three placebo infusions, with follow-up through 88 weeks. At week 62, the three-infusion group had a higher proportion of participants meeting the study’s prespecified motor-score improvement threshold than the placebo group. Reported adverse events were mild and transient. These findings add to ongoing research on repeated allogeneic MSC infusions for Parkinson’s disease.

2021: Single-Dose Allogeneic MSC Study Reported Safety Findings

Allogeneic Bone Marrow-Derived Mesenchymal Stem Cell Safety in Idiopathic Parkinson’s Disease — Read Study

This open-label phase I study enrolled 20 people with mild-to-moderate Parkinson’s disease who received one intravenous infusion of allogeneic bone-marrow-derived MSCs at one of four doses. The primary goal was to assess safety and tolerability over 12 months. The investigators reported no serious infusion reactions or donor-specific immune responses. Dyskinesia and hypertension were the most commonly reported treatment-emergent events, each occurring in four participants, and one possibly related serious adverse event was reported. The study also evaluated inflammatory markers and motor scores, contributing early clinical information on intravenous MSC treatment for Parkinson’s disease.