Weight Loss In Parkinson's Disease Research Articles

Resistance to high-fat diet-induced weight gain in transgenic mice overexpressing human wild-type α-synuclein: A model for metabolic dysfunction in Parkinson's disease.

Unintentional weight loss, primarily due to the loss of fat mass rather than muscle mass, is common among patients with Parkinson's disease (PD) and is associated with poor quality of life and accelerated disease progression. Since transgenic mice overexpressing human wild-type α-synuclein (α-Syn mice) are modestly leaner than control mice, and since diabetes, a metabolic disorder, is a major risk factor for PD, we reasoned that high-fat diet-induced diabetes/metabolic dysregulation in α-Syn mice may serve as a robust tool for exploring how early α-synuclein pathology contributes to metabolic dysregulation, leading to weight loss in PD. Thus, α-Syn and age-matched controls were fed a high-fat diet (HFD) chow (60% fat calories) ad libitum for four months. Compared with controls on HFD (control-HFD), α-Syn mice on HFD (α-Syn-HFD) were dramatically leaner. The resistance to gaining weight in α-Syn-HFD mice was accompanied by improved glucose tolerance, a dramatic decrease in fat mass, and an increase in energy expenditure. Despite this leaner phenotype and better glucose tolerance, the mortality was much higher in male α-Syn-HFD mice than in all controls, but was unaffected in females, suggesting protective effects of female sex hormones, as well as lower α-synuclein levels. Immunoblot analysis of insulin signaling in the olfactory bulb, the proposed initial seeding site of α-synuclein pathology, revealed a decrease of IGF-IRβ, p GSK, and p mTOR in α-Syn-HFD mice. Since GSK-3β and mTOR regulate synaptic plasticity, we assessed levels of PSD-95 and synaptophysin in the olfactory bulb. As anticipated, we observed a significant decrease in the levels of PSD-95, along with a potentially compensatory increase in synaptophysin levels. Our results show that α-Syn mice, when challenged with diet-induced diabetes/metabolic dysregulation, clearly reveal a profile of robust metabolic dysfunction, thus providing a sensitive tool for assessing the underlying mechanism of metabolic dysfunction and its impact on weight loss and disease progression in PD. We propose a role for olfactory dysfunction in PD-related unintentional weight loss and suggest that strategies aimed at increasing body weight/BMI will improve the quality of life and prognosis for people living with PD.

Author response: Early weight loss in parkinsonism predicts poor outcomes: Evidence from an incident cohort study.

We thank Dr. Marinelli for the comment on our article,1 and agree that further research into the relationship between protein misfolding and weight loss in Parkinson disease (PD) is needed. Furthermore, several other potential mechanisms for weight loss deserve further study, including other aspects of brain metabolism, whole-body metabolic rate, appetite regulation, and food-related reward mechanisms.

Brown adipose tissue activation in a rat model of Parkinson's disease.

Loss of body weight and fat mass is one of the nonmotor symptoms of Parkinson's disease (PD). Weight loss is due primarily to reduced energy intake and increased energy expenditure. Whereas inadequate energy intake in PD patients is caused mainly by appetite loss and impaired gastrointestinal absorption, the underlying mechanisms for increased energy expenditure remain largely unknown. Brown adipose tissue (BAT), a key thermogenic tissue in humans and other mammals, plays an important role in thermoregulation and energy metabolism; however, it has not been tested whether BAT is involved in the negative energy balance in PD. Here, using the 6-hydroxydopamine (6-OHDA) rat model of PD, we found that the activity of sympathetic nerve (SN), the expression of Ucp1 in BAT, and thermogenesis were increased in PD rats. BAT sympathetic denervation blocked sympathetic activity and decreased UCP1 expression in BAT and attenuated the loss of body weight in PD rats. Interestingly, sympathetic denervation of BAT was associated with decreased sympathetic tone and lipolysis in retroperitoneal and epididymal white adipose tissue. Our data suggeste that BAT-mediated thermogenesis may contribute to weight loss in PD.

Reduced Body Mass Index in Parkinson’s Disease

Courses of Parkinson's disease (PD) that are complicated by weight loss result in poorer overall treatment outcome and lower quality of life. To determine the contribution of depression, which has not yet been specified in the etiology of weight loss in PD, symptomatology and anamnesis from 215 outpatients diagnosed with PD were assessed using a comprehensive battery of neuropsychiatric scales. A percentage of 31 comorbid depressed patients and a comparison with a control population allowed an accurate characterization of effect sizes, sex differences, and patterns of the contribution of comorbid depression to weight loss. Our study showed that comorbid depression had a clinically relevant effect concerning reduced body mass index in male (0.3; Hedges' g) but not in female PD patients. Although some possible confounders are not controlled here, our results support the need of monitoring depressive symptoms in the courses of PD, particularly in male patients.

Dopaminergic treatment is associated with decreased body weight in patients with Parkinson’s disease and dyskinesias

Several studies suggested that patients with advanced Parkinson's disease (PD) showed a too low body weight when compared with age-matched, healthy subjects. We aimed to investigate whether PD patients with dyskinesias display body weight alterations and to observe any correlations between medication and other putative determinants. Charts of 166 PD patients with fluctuations and dyskinesias, admitted within 6 months to a German movement disorders clinic, were investigated for body mass index (BMI), age at onset, disease duration, Unified Parkinson's Disease Rating Scale motor score, eating coordination and medication. Analysis showed that 4.2% of PD patients were underweight (BMI < 18.5 kg/m(2)), 46.4% were normal (BMI > 18.5-25 kg/m(2)), 33.7% were overweight (BMI > 25-30 kg/m(2)), 15.7% were obese (BMI > 30 kg/m(2)). Daily levodopa dosage per kg and total dopaminergic dosage per kg body weight were negatively correlated with BMI. Overall, patients' BMI had not significantly changed within 2 years of follow-up. In sum, advanced PD patients showed a reduced BMI when compared with a control population obtained from an age-matched group taken from a survey of the German Federal Office for Statistics. Our findings indicate that patients with a lower BMI received a higher cumulative levodopa dosage and that levodopa may be responsible for weight loss in PD.

Weight loss in Parkinson’s disease

Weight loss is frequent in patients with Parkinson's disease (PD). Reduced energy intake and/or increased energy expenditure have been postulated as the cause. Dysphagia, anorexia, and gastrointestinal dysfunction may be possible causes of reduced energy intake; whereas, rigidity, tremor, and levodopa-induced dyskinesia may increase energy expenditure. Levodopa may enhance glucose metabolism resulting in enhanced energy expenditure. Depression, anti-parkinsonian drugs, and medical complications such as pneumonia and malignancies also may facilitate weight loss in PD. Combinations of various degrees of these factors, especially in advanced PD, may produce weight loss. Such weight loss is associated with malnutrition which may precipitate infection and decubitis; accelerate motor, behavioral, and autonomic impairment; consequently spoiling one's quality of life. Attention must be paid as well to motor symptoms to prevent or reverse weight loss in PD patients.

Predictors of weight loss in Parkinson's disease

The objective of this study was to examine the change of body weight (BW) among Parkinson's disease (PD) patients and controls over years and determine the predictors of weight loss among PD patients. Studies on weight loss in PD studies are cross-sectional, have a short follow-up, or lack in clinical detail. We examined the percentage of BW change over years among 49 PD patients and 78 controls. The controls were from another study on longitudinal evolution of BW and body composition in the elderly. We determined the BW, Hoehn and Yahr (HY) stage, and dyskinesia status of 49 consecutive nondemented PD patients with symptom duration of 6.1 +/- 0.7 years (mean +/- SEM) and ascertained their BW at the time of diagnosis and 2.4 +/- 0.2 years before the diagnosis from medical records. We collected data again 7.2 +/- 0.5 years after the first visit. The PD group lost 7.7% +/- 1.5% of BW over the entire symptomatic period (13.1 +/- 0.8 years), while the control group lost only 0.2% +/- 0.7% of BW over 9.9 +/- 0.1 years; weight loss was clinically significant (>5%) in 55.6% of PD patients vs. 20.5% of the controls (both P values < 0.001, adjusted for sex, baseline age, and observation period duration). PD patients lost weight in both the early and advanced phases. While worsening of parkinsonism was the most important factor, age at diagnosis, emergence of visual hallucinations, and possibly dementia were also associated with weight loss. We demonstrated significant weight loss in PD patients compared to controls over approximately 1 decade. Neurodegeneration involving both motor and nonmotor systems may be associated with weight loss in PD.

Low body weight in Parkinson's disease.

Low body weight is a characteristic symptom of Parkinson's disease (PD), but the mechanism is unknown. To determine whether bulbar involvement is responsible for the weight loss, we compared the mean body weight (MBW), height, and body mass index (BMI) of 281 patients with PD and 86 patients with progressive supranuclear palsy (PSP). Although the patients with PSP had significantly worse dysphagia and dysarthria than the patients with PD, their MBW and BMI were not appreciably different. We conclude that bulbar dysfunction is not the reason for weight loss in PD.