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Biomarkers Identified That Could Help Predict Individuals at Risk for Parkinson’s, Study Says

DOPA, DOPAC levels

Low levels of two dopamine-related molecules in cerebrospinal fluid can help identify patients in the early stages of preclinical Parkinson’s disease, a study suggests.

The study, “Cerebrospinal fluid biomarkers of central dopamine deficiency predict Parkinson’s disease,” was published in Parkinsonism & Related Disorders.

Parkinson’s disease is mainly recognized by its motor symptoms, such as uncontrolled tremors, gait difficulties, and slow movement. However, by the time these symptoms appear, a significant loss of brain cells sensitive to dopamine has already occurred.

Because of this, there is a need for sensitive markers of early brain cell loss that can be used to track disease progression.

DOPAC and DOPA are two dopamine-related molecules whose levels are reduced in patients with untreated Parkinson’s. However, it was not clear if measuring levels of both proteins could help identify asymptomatic, healthy people who are at risk of developing Parkinson’s disease.

A team led by David Goldstein, MD, PhD, principal investigator at the National Institutes of Health, evaluated the levels of DOPAC and DOPA in cerebrospinal fluid samples collected from 26 at-risk people.

This analysis was integrated in the PDRisk prospective study of the National Institute of Neurological Disorders and Stroke (NINDS), which intends to identify early biomarkers of Parkinson’s disease.

Participants had to have at least three previously defined risk factors for Parkinson’s disease, including direct family history of the disease, loss of sense of smell, impaired sleep or abnormal sleep behavior, and low resting blood pressure.

Patients who were already showing signs of Parkinson’s-related motor symptoms during the enrollment phase were excluded from the study.

Of the 26 participants, four developed clinical Parkinson’s disease during the three-year follow-up period. These patients were found to have significantly lower levels of both DOPA and DOPAC in cerebrospinal fluid than the 22 participants who did not develop Parkinson’s for at least a mean follow-up of 4.2 years.

Researchers determined that the optimal cutoff value for defining low diagnostic DOPAC was 1.22 pmol/mL, which accurately predicted Parkinson’s risk in 84.1% of cases. For DOPA, the cutoff value was 2.63 pmol/mL, accurately predicting disease risk in 90.3% of cases.

These data suggest that early dopamine deficiency in at-risk individuals — defined by low DOPAC and DOPA levels — is linked to an increased likelihood of developing clinical Parkinson’s disease within three years.

Researchers believe the identified “predictive strength” reflects the important role of these neurochemical biomarkers in the underlying mechanisms of disease, suggesting that “neurochemical biomarkers of central dopamine deficiency identify the disease in a pre-clinical phase.”

The post Biomarkers Identified That Could Help Predict Individuals at Risk for Parkinson’s, Study Says appeared first on Parkinson’s News Today.

Source: Parkinson's News Today

Vitamin B12 Supplements May Help Slow Parkinson’s Progression, Study Finds

Vitamin B12 supplement

Low levels of vitamin B12 in patients in the early stages of Parkinson’s disease are linked to faster motor and cognitive decline, suggesting that vitamin supplements may help slow the progression of these symptoms, a study has found.

The study, “Vitamin B12 and homocysteine levels predict different outcomes in early Parkinson’s disease,” was published in the journal Movement Disorders.

Several previous studies have shown that B12 deficiencies are common in Parkinson’s patients. Deficiency of this vitamin promotes development of neurological and motor symptoms associated with the disease, including depression, paranoia, muscular numbness, and weakness.

While most studies have addressed the association of B12 with more advanced Parkinson’s disease, little is known about its contribution in the early stages of the disease before treatment begins.

University of California San Francisco (UCSF) researchers analyzed B12 levels in 680 patients recently diagnosed with Parkinson’s who had not begun treatment. The participants were followed for two years, during which physical and cognitive evaluations were conducted, in addition to B12 assessments. After initial evaluations, the patients were given the option to take a controlled daily multivitamin supplement.

Patients were divided into three groups according to their B12 levels at the beginning of the study. Approximately 13% of the participants had borderline low levels of B12, and 5% had a B12 deficiency. No association was found between low vitamin levels and early motor or cognitive symptoms of Parkinson’s.

The team did find that over time, symptoms in patients with lower B12 levels developed more rapidly than those with higher levels: Patients with lower B12 levels had a significantly reduced ambulatory capacity than patients with higher levels.

“Our findings demonstrate that low B12 levels are associated with greater walking and balance problems, possibly due to the known effect of B12 deficiency on the central and peripheral nervous systems,” Chadwick Christine, MD, UCSF neurologist and lead author of the study, said in a university press release. “Alternatively, low B12 may have a direct effect on the progression of Parkinson’s disease, or it may be a marker of an unknown associated factor, perhaps correlating with another aspect of the disease or nutritional status.”

Subsequent analysis showed improved B12 levels in about 50% of participants, indicating they had chosen to take the multivitamin supplement. Disease progression in this group of patients was found to be much slower, based on the annualized average increase of disability on the Unified Parkinson’s Disease Rating Scale (UPDRS) score  — a measure of Parkinson’s disability. Patients with improved B12 levels had an increase to only 10.11 on the scale, showing less disability, compared with 14.38 in patients who maintained low B12 levels throughout the study.

The team also evaluated the blood levels of homocysteine, an amino acid that is usually elevated in people with low B12 levels. There was a significant association between high levels of homocysteine — thus lower B12 — and faster cognitive decline.

“Our results suggest that the measurement of B12 levels early in Parkinson’s may be beneficial,” Christine said. “If levels are at the low end of normal, supplementation to get the level into the middle or upper end of the normal range may slow development of symptoms.”

Further studies are warranted to shed light on how vitamin B12 might benefit Parkinson’s patients, and to fully address its therapeutic potential on disease progression.

The study was supported by funding from the Michael J. Fox Foundation, and gifts from the Ko and Tsu family and William and Mary Ann S. Margaretten.

The post Vitamin B12 Supplements May Help Slow Parkinson’s Progression, Study Finds appeared first on Parkinson’s News Today.

Source: Parkinson's News Today