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Specific BDNF Mutation May Be Linked to Higher Risk of Cognitive Impairment in Parkinson’s, Study Suggests

BDNF gene mutation

One amino acid change in the brain-derived neurotrophic factor (BDNF) gene, which provides instructions for a protein important to neuronal survival, may be associated with cognitive impairment in Parkinson’s disease patients, a study has found.

The study, “BDNF Val66Met polymorphism and cognitive impairment in Parkinson’s disease—a meta-analysis,” was published in the journal Neurological Sciences.

BDNF protein is produced inside brain cells and is crucial for their function as well as supporting their growth and protecting them against premature cell death. When its coding sequence is changed, this can have a major impact on brain cell outcomes.

Previous studies have suggested that one specific BDNF gene mutation called Val66Met that results in the change of a valine (Val) by a methionine (Met) at position 66 — both amino acids, also known as the protein’s building blocks — could be linked to cognitive impairment in Parkinson’s disease. However, there is no consensus on the relevance of this genetic mutation on outcomes of Parkinson’s patients.

Chinese researchers searched for available literature on this matter, and analyzed pooled data from six studies involving a total of 1,467 patients with Parkinson’s disease. These studies had been carried out in Italy, Spain, Poland, Brazil, Belgrade (Serbia), and the Netherlands.

Results revealed a significant association between the Val66Met BDNF mutation and risk of Parkinson’s disease-related cognitive impairment. Patients who had two copies of the BDNF gene with methionine (mutated version) were found to have a 3.82 times higher risk of developing cognitive impairment than those who had two BDNF copies with valine (non-mutated version).

However, it’s worth mentioning that the studies in this analysis only included Caucasian study samples, so these results should not be generalized to other ethnicities.

Parkinson’s disease affects people of all races and ethnicity worldwide. Some studies indicate that neurodegenerative disorders affect more white people than any other ethnicity, but a solid conclusion cannot be drawn from available research as they tend to vary widely regarding diagnostic criteria, sample sizes, and methodology.

“Future studies should verify our findings in larger populations, particularly in other ethnicities,” the researchers wrote.

Still, the team believes that this study provides evidence that mutated BDNF “may be associated with increased risk of cognitive impairment of Parkinson’s disease, at least among Caucasians.”

In addition, this Val66Met change in the BDNF sequence should be studied in different Parkinson’s patients presenting tremor dominant or postural instability gait disorders. Further understanding of the impact of genetics on the long-term outcomes of these patients “may better guide clinical treatments and judge the prognosis,” they said.

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Hydrotherapy Improves Balance, Mobility in Parkinson’s Patients, Study Reports

hydrotherapy

Hydrotherapy may provide significant balance and mobility benefits in patients with Parkinson’s disease compared to medication and land-based exercises, according to a review study.

The research, “The Effects of Hydrotherapy on Balance, Functional Mobility, Motor Status, and Quality of Life in Patients with Parkinson Disease: A Systematic Review and Meta-analysis,” was published in the journal PM&R.

Impairments such as muscle rigidity and tremor affect the balance and mobility of people with Parkinson’s. Combined with fear of falling, it promotes a sedentary lifestyle and reduces quality of life.

Water-based exercise is often prescribed to these patients, providing a safe environment that reduces the risk of falling. Prior studies have reported that hydrotherapy improves motor symptoms. However, the evidence about  hydrotherapy as a treatment strategy in Parkinson’s is scarce.

To address this gap, researchers conducted a systematic review of the available scientific literature and a meta-analysis — a type of statistical analysis that combines the results of various studies.

The scientists focused on hydrotherapy’s effectiveness on patients’ balance, mobility, quality of life and motor function.

For this purpose, the investigators searched seven online databases as well as unpublished or ongoing clinical trials from inception through December 2017. Nineteen studies were identified, of which eight were randomized controlled trials (RCTs). Overall, the studies had 484 participants, with a mean age ranging from 54 to 78 years and an average disease duration ranging from three to 10 years.

The studies had different designs, which included comparisons of hydrotherapy with land-based exercises or medications, combinations of hydrotherapy with land-based therapy, and assessments of low-intensity and muscular resistance water-based exercises.

Hydrotherapy could include balance training, stretching, strengthening, trunk mobility, and gait exercises. The sessions ranged from 40 to 60 minutes, one to five days per week, for three to 20 weeks, for a total of eight to 60 sessions. Water temperature was set between 28ºC (82ºF) and 34ºC (93ºF) in the 12 studies that reported this parameter.

All but two studies with available information on levodopa usage evaluated patients’ in the “on” phase, which refers to the period when this medication is effective and has not yet worn off.

The meta-analysis on balance and mobility included five RCTs, which had a total of 133 patients. The results showed that hydrotherapy with or without land-based exercises significantly improved both balance and mobility compared to land-based therapy or usual care with medication alone.

Three other studies not included in the meta-analysis due to lacking a control group also found significant benefits with hydrotherapy in balance. One RCT not included in the statistical comparison did not report differences with hydrotherapy and land-based therapy, while another showed that aquatic obstacles training is more beneficial for balance than traditional water-based exercises.

In turn, two RCTs not included in the respective analysis failed to show mobility improvements with hydrotherapy.

As for quality of life, an analysis of three RCTs with 76 patients showed no benefits with hydrotherapy compared to land-based treatment, which the researchers attributed to the small number of studies included. This also was observed in one RCT not included in the meta-analysis. In contrast, five other studies, including two non-randomized trials, found significant improvements with water-based treatment.

Results of a meta-analysis of five RCTs with 140 patients also did not reveal improvements in motor function in comparison to land-based exercise. This can be explained by patients having types of motor complications not expected to improve with hydrotherapy, the team said.

Of note, two other RCTs and a non-randomized trial also did not find different results with hydrotherapy compared to other approaches in motor function.

Overall, the scientists wrote, “hydrotherapy, combined or not with other therapies, may improve balance and functional mobility of patients with [Parkinson’s] when compared to land-based therapy alone or usual care.”

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Hypertension May Increase Risk of Parkinson’s, Study Reports

hypertension, Parkinson's risk

Patients with hypertension may be at a higher risk for Parkinson’s disease, according to a review of population-based studies.

The review, “Association between Hypertension and the Risk of Parkinson’s Disease: A Meta-Analysis of Analytical Studies,” appeared in the journal Neuroepidemiology.

Hypertension may cause damage in blood vessels in specific brain areas, such as the basal ganglia, which contain the substantia nigra and the striatum. In Parkinson’s, the substantia nigra experiences progressive loss of dopamine-producing neurons while the striatum has low levels of this neurotransmitter. This suggests a link between hypertension and greater prevalence of Parkinson’s.

However, previous studies have had contradictory findings, with some reporting a greater risk and others suggesting a lower risk for Parkinson’s.

To clarify this link, scientists from Qingdao University in China conducted a meta-analysis — a statistical study that combines the results of various studies — and a systematic review of the available literature.

Seven online databases were searched for literature up to July 13, 2018. From these databases, 27 observational studies were included, nine of which were population-based cohort studies (with a total of 1,230,085 participants) and 18 were case-control studies (32,121 participants). All but one study were from either North America, Europe, or Asia.

Five studies assessed hypertension by medical record, 11 through questionnaire, and two by measuring blood pressure.

In the cohort studies — prospective analyses where groups are followed to compare the risk of a specific outcome — patients with hypertension were at a significantly greater risk for Parkinson’s than participants with normal blood pressure. This was confirmed after excluding the two studies that were leading to high variability of results.

“Based on population-based cohort studies, this meta-analysis indicated hypertension might increase the risk of [Parkinson’s],” the researchers wrote.

In contrast, case-control studies — retrospective analyses where participants with or without hypertension are known from the start — suggested that hypertension might lower the risk for Parkinson’s. However, a subgroup analysis based on non-hospital records revealed no association. The variability observed in these studies was mainly due to different results in controls, depending on whether they were from hospital settings or not.

According to the team, the contradictory results in the two types of studies may have been due to a higher proportion of elderly controls with hypertension in case-control studies, particularly those conducted in the hospital setting.

Due to the link between aging and both hypertension and Parkinson’s, these studies are not suitable for exploring the risk of Parkinson’s in hypertension, the researchers said.

Among the study’s limitations, they mentioned not accounting for the use of anti-hypertensive medications as well as not being able to calculate an overall risk for Parkinson’s combining the two types of studies.

The post Hypertension May Increase Risk of Parkinson’s, Study Reports appeared first on Parkinson’s News Today.

Inflammatory Bowel Disease Linked to Risk of Parkinson’s in Large Review Study

People with inflammatory bowel disease (IBD), an umbrella name for disorders marked by prolonged inflammation of the digestive tract, are at a higher-than-usual risk for Parkinson’s disease, a review study involving 8.9 million IBD patients suggests.
The study, “The risk of Parkinson’s disease in inflammatory bowel disease: A systematic review and meta-analysis,” was published in the journal Digestive and Liver Disease.
Inflammatory bowel disease (IBD) is a term that includes two main disorders — ulcerative colitis and Crohn’s disease — and is characterized by an imbalanced immune response that triggers prolonged inflammation of the digestive tract.
Inflammation in ulcerative colitis is confined to the colon (large intestine), while in Crohn’s disease it can involve any part of the digestive system. But inflammation in Crohn’s is most common at the end of the ileum (the last section of the small intestine) or the colon.
Several studies have reported that some of the inflammatory pathways impaired in Parkinson’s are also found in IBD. Certain population-based studies have also reported an increased prevalence of Parkinson’s among IBD patients, but the link between both disorders remains controversial. Another follow-up study failed to confirm those initial findings.
Researchers in China conducted a meta-analysis of published literature focusing on Parkinson’s risk in IBD using two databases, PubMed and Embase, and including in their search the keywords “ulcerative colitis” and “Crohn’s disease.” For the meta-analysis, they included cohort or case-control studies with patients diagnosed with IBD, either ulcerative colitis and Crohn’s disease, and whose main outcome was Parkinson’s.
Out of an initial pool of 172 studies, four studies accounting for a total of more than 8.9 million patients were included in the meta-analysis. (A meta-analysis is a statistical technique used to summarize in a quantitative manner the findings of multiple studies.)
Performed in the United States, Denmark, Sweden and Taiwan, these four studies assessed the incidence rate of Parkinson’s in IBD patients, specifically those with Crohn’s and ulcerative colitis. Three had been conducted in 2018, and one in 2016.
“To our knowledge, this is the first MA [meta-analysis] to focus on the risk of PD [Parkinson’s] in IBD patients,” the research team wrote. “Despite the small number of studies included, the patient numbers were large due to the population-based nature of the included studies.”
Pooled results of all studies suggested that an IBD diagnosis was associated with a 41% increased risk of developing Parkinson’s.
Assessing the risk of ulcerative colitis and Crohn’s disease separately, researchers found that both disease subtypes were linked to a higher Parkinson’s risk compared with age- and sex-matched controls — Crohn’s patients had a 28% higher risk of Parkinson’s, and those with ulcerative colitis a 30% increased risk, the study reported.
Among the IBD patients, the risk for Parkinson’s was not affected by gender, with similar rates seen in male and female patients, or by age.
Overall, this meta-analysis “identified an increased risk of PD in IBD patients,” the reseachers wrote, which “remained significant when separately analysing CD [Crohn’s disease] and UC [ulcerative colitis] subgroups.”
“More comprehensive and detailed MA using a larger number of studies are required to validate our

Source: Parkinson's News Today