Can fatigue predict walking capacity of patients with Parkinson's disease?

Although fatigue is an expressive symptom of Parkinson's disease (PD), few studies have investigated the association between fatigue, mobility and walking capacity of these patients. OBJECTIVE: To investigate whether fatigue is an independent factor associated with mobility and the walking capacity in patients with PD. METHODS: Forty-eight patients with PD (22 with fatigue) were tested for mobility and their walking capacity: Timed Up and Go (TUG), 10-Meter Walk Test (10MWT) at usual and fastest speed, and 6-Minute Walk Test (6MWT). Fatigue was measured with Parkinson's Fatigue Scale (PFS-16). Linear regression analysis was used to investigate if fatigue is an independent factor contributing to variance in mobility and walking capacity. RESULTS: There was a positive correlation between PFS-16 and TUG (rs=0.385; p=0.007). There was a negative correlation between PFS-16 and 10MWT at comfortable (r=-0.385; p=0.007) and fast speeds (r=-0.396; p=0.005), and 6MWT (r=-0.472; p=0.001). Linear regression analysis revealed that fatigue did not explain the variance of TUG and 10MWT. PFS-16, age and section III of UPDRS explained 49.6% (adjusted R2; p<0.001) variance in the 6MWT, and fatigue was the most significant predictor (F=-32.1; p=0.022). CONCLUSIONS: Fatigue is an independent factor contributing to the distance covered during 6MWT in patients with PD. Our results highlight the importance of recognition and management of this symptom.

Can fatigue predict walking capacity of patients with Parkinson's disease? / A fadiga pode predizer a mobilidade e a capacidade de marcha em pacientes com doença de Parkinson?

ABSTRACT Although fatigue is an expressive symptom of Parkinson's disease (PD), few studies have investigated the association between fatigue, mobility and walking capacity of these patients. Objective: To investigate whether fatigue is an independent factor associated with mobility and the walking capacity in patients with PD. Methods: Forty-eight patients with PD (22 with fatigue) were tested for mobility and their walking capacity: Timed Up and Go (TUG), 10-Meter Walk Test (10MWT) at usual and fastest speed, and 6-Minute Walk Test (6MWT). Fatigue was measured with Parkinson's Fatigue Scale (PFS-16). Linear regression analysis was used to investigate if fatigue is an independent factor contributing to variance in mobility and walking capacity. Results: There was a positive correlation between PFS-16 and TUG (rs=0.385; p=0.007). There was a negative correlation between PFS-16 and 10MWT at comfortable (r=-0.385; p=0.007) and fast speeds (r=-0.396; p=0.005), and 6MWT (r=-0.472; p=0.001). Linear regression analysis revealed that fatigue did not explain the variance of TUG and 10MWT. PFS-16, age and section III of UPDRS explained 49.6% (adjusted R2; p<0.001) variance in the 6MWT, and fatigue was the most significant predictor (F=-32.1; p=0.022). Conclusions: Fatigue is an independent factor contributing to the distance covered during 6MWT in patients with PD. Our results highlight the importance of recognition and management of this symptom.

RESUMO Embora a fadiga seja um sintoma importante na doença de Parkinson (DP), poucos estudos investigaram a associação entre fadiga, mobilidade e capacidade de marcha nesses pacientes. Objetivo: Investigar se a fadiga é um fator independente associado à mobilidade e à capacidade de marcha em pacientes com DP. Métodos: Quarenta e oito pacientes com DP (22 com fadiga) foram avaliados com testes de mobilidade e capacidade de marcha: Timed Up and Go (TUG), Teste de Caminhada de 10 metros (T10m) na velocidade usual e máxima, Teste de Caminhada de Seis Minutos (TC6m). A fadiga foi medida pela Escala de Fadiga no Parkinson (PFS-16). A análise de regressão linear foi utilizada para investigar se a fadiga é um fator independente que contribui para a variação na mobilidade e capacidade de marcha. Resultados: Houve correlação positiva entre PFS-16 e TUG (rs=0,385; p=0,007). Houve correlação negativa entre PFS-16 e T10m na velocidade usual (r=-0,385; p=0,007) e máxima (r=-0,396; p=0,005) e TC6m (r=-0,472; p=0,001). Análise de regressão linear revelou que a fadiga não explicava a variância do TUG e T10m. A PFS-16, a idade e a seção III da UPDRS explicaram 49,6% (R2 ajustado, p<0,001) da variância no TC6m e a fadiga foi o preditor mais significativo (F=-32,1; p=0,022). Conclusões: A fadiga é um fator independente que contribui para a distância percorrida durante o TC6m em pacientes com DP. Nossos resultados destacam a importância do reconhecimento e manejo desse sintoma.

Sympathetic glial cells and macrophages develop different responses to Trypanosoma cruzi infection or lipopolysaccharide stimulation

Nitric oxide (NO) participates in neuronal lesions in the digestive form of Chagas disease and the proximity of parasitised glial cells and neurons in damaged myenteric ganglia is a frequent finding. Glial cells have crucial roles in many neuropathological situations and are potential sources of NO. Here, we investigate peripheral glial cell response to Trypanosoma cruzi infection to clarify the role of these cells in the neuronal lesion pathogenesis of Chagas disease. We used primary glial cell cultures from superior cervical ganglion to investigate cell activation and NO production after T. cruzi infection or lipopolysaccharide (LPS) exposure in comparison to peritoneal macrophages. T. cruzi infection was greater in glial cells, despite similar levels of NO production in both cell types. Glial cells responded similarly to T. cruzi and LPS, but were less responsive to LPS than macrophages were. Our observations contribute to the understanding of Chagas disease pathogenesis, as based on the high susceptibility of autonomic glial cells to T. cruzi infection with subsequent NO production. Moreover, our findings will facilitate future research into the immune responses and activation mechanisms of peripheral glial cells, which are important for understanding the paradoxical responses of this cell type in neuronal lesions and neuroprotection.

Interferon-gamma induced nitric oxide mediates in vitro neuronal damage by Trypanosoma cruzi-infected macrophages.

Neuronal lesions and peripheral denervation in Chagas' disease are related to local inflammation; however, the pathogenic mechanisms of neuronal lesions in the heart and megavisceras are still unclear. We investigated the involvement of nitric oxide (NO) on neuronal lesion in co-cultures of neurons and macrophages. Trypanosoma cruzi-infected and interferon-gamma (IFN-gamma)-activated co-cultures of neurons and wild-type (WT) macrophages showed significant reduction of both neuronal survival and neurite density. These findings correlated with the levels of NO and the expression of inducible nitric oxide synthase (iNOS). Accordingly, neuronal survival rate in the co-cultures was recovered to control levels by treatment of the cultures with the iNOS inhibitor, aminoguanidine. Moreover, neither neuronal survival nor the neurite density was affected in the co-cultures when the macrophages were harvested from iNOS-deficient mice. These results demonstrate that iNOS-derived NO is the major molecule involved in neuronal damage mechanism in our in vitro model of Chagas' disease neuropathology.