Mortality in levodopa-treated Parkinson's disease

Effect of Early Levodopa Treatment on Mortality in People with Parkinson's Disease

BACKGROUND

The ideal timing for initiating levodopa in newly diagnosed people with Parkinson's disease (PD) is uncertain due to limited data on the long-term effects of levodopa.

OBJECTIVE

The aim was to investigate whether early levodopa initiation postpones mortality (primary outcome), the requirement of device-aided therapies, and the incidence of PD-related complications, such as fall-induced injuries.

METHODS

Using nationwide claims data from Dutch hospitals (2012-2020), we grouped newly diagnosed PD individuals as "early initiators" (initiating levodopa within 2 years of diagnosis) or "nonearly initiators." We used the national death registry to assess mortality and health-care claims to assess PD-related complications and device-aided therapies. We used marginal structural models to compare mortality and device-aided therapy rates between groups, and a Poisson regression model to compare PD-related complication rates.

RESULTS

Among 29,943 newly diagnosed PD individuals (mean age at diagnosis: 71.6, 38.5% female), there were 24,847 early and 5096 nonearly levodopa initiators. Over a median 4.25 years, 8109 (27.1%) died. The causal risk ratio for mortality was 1.04 (95% confidence interval [CI] 0.92-1.19) for early versus nonearly initiators. The risk ratio of receiving any device-aided therapy was 3.19 (95% CI 2.56-5.80). No association was observed with incidence of PD-related complications (incidence rate ratio: 1.00, 95% CI 0.96-1.05).

CONCLUSIONS

Early levodopa initiation in PD does neither postpone nor accelerate mortality or PD-related complications, nor does it precipitate earlier occurrence of PD-related complications or mortality. However, we cannot exclude that the results were influenced by residual confounding due to unmeasured risk factors of mortality.

Supplementation of probiotic Bifidobacterium breve Bif11 reverses neurobehavioural deficits, inflammatory changes and oxidative stress in Parkinson's disease model

Human gut microbiota are thought to affect different physiological processes in the body, including brain functions. Gut dysbiosis has been linked to the progression of Parkinson's disease (PD) and thus, restoring the healthy gut microbiota with supplementation of putative probiotic strains can confer some benefits in PD. In the current study, we explored the neuroprotective potential of Bifidobacterium breve Bif11 supplementation in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine hydrochloride (MPTP) treated female Sprague Dawley rats. This study investigated the behavioural, molecular and biochemical parameters in the MPTP rat model. A pharmacological intervention of Bif11 at doses of 1 × 1010 CFU and 2 × 1010 CFU for 21 days was found to attenuate the cognitive and motor changes in the MPTP rat model. Furthermore, it also increased the tyrosine hydroxylase levels, reduced pro-inflammatory markers and decreased oxidative and nitrosative stress in the mid brain of MPTP-lesioned rats. Bif11 supplementation even restored the levels of short-chain fatty acids and decreased intestinal epithelial permeability in MPTP-induced PD model rats. In summary, these findings demonstrate that B. breve Bif11 has the potential to ameliorate symptoms of PD. However, this therapy needs to be further investigated with in-depth mechanistic insights in the future for the treatment of PD.

Sex Differences in the Speech of Persons With and Without Parkinson's Disease

BACKGROUND

Sex differences are apparent in the prevalence and the clinical presentation of Parkinson's disease (PD), but their effects on speech have been less studied.

METHOD

Speech acoustics of persons with (34 females and 34 males) and without (age- and sex-matched) PD were examined, assessing the effects of PD diagnosis and sex on ratings of dysarthria severity and acoustic measures of phonation (fundamental frequency standard deviation, smoothed cepstral peak prominence), speech rate (net syllables per second, percent pause ratio), and articulation (articulatory-acoustic vowel space, release burst precision).

RESULTS

Most measures were affected by PD (dysarthria severity, fundamental frequency standard deviation) and sex (smoothed cepstral peak prominence, net syllables per second, percent pause ratio, articulatory-acoustic vowel space), but without interactions between them. Release burst precision was differentially affected by sex in PD. Relative to those without PD, persons with PD produced fewer plosives with a single burst: females more frequently produced multiple bursts, whereas males more frequently produced no burst at all.

CONCLUSIONS

Most metrics did not indicate that speech production is differentially affected by sex in PD. Sex was, however, associated with disparate effects on release burst precision in PD, which deserves further study.

SUPPLEMENTAL MATERIAL

https://doi.org/10.23641/asha.24388666.

Mortality rates for Parkinson's disease are increasing in Spain. An Age-Period-Cohort and Joinpoint Analysis in Mortality Rates from 1981 to 2020

BACKGROUND

Mortality in Parkinson's disease is increasing worldwide, but Spanish data need further study.

OBJECTIVE

To analyse the mortality trends of Parkinson's disease in Spain between 1981 and 2020.

METHODS

This observational retrospective study assessed the Parkinson's disease mortality data from 1981 to 2020 were collected from the National Statistics Institute of Spain. Age-standardized mortality rates were analysed by age and sex groups, detecting significant mortality trends through a joinpoint analysis. Age-period-cohort effect and potential years of life lost analyses were conducted. The European standard population of 2013 was considered for the analyses.

RESULTS

A total of 88,034 deaths were assessed. The overall age-standardized mortality rate rose throughout the period from 3.67 to 8.57 per 100,000 inhabitants. Mortality rates in men were higher than in women, 11.63 versus 6.57 deaths per 100,000 inhabitants. The sex ratio showed an increase in premature mortality in men during 2020. The overall joinpoint analysis recorded a rise in mortality, primarily since the twentieth century, mainly in male and older groups, that matched with a period effect. The age effect was detected, confirming higher mortality at an older age. The analysis of potential years of life lost detected a growth in this rate, changing from 0.66 in 1981 to 1.06 in 2020.

CONCLUSIONS

Mortality data for Parkinson's disease in Spain rose significantly in forty years. Mortality rate was higher in the male and age group above 75 years of age. The sex ratio showed premature mortality in men in 2020, which will need further study.

Effects of non-invasive brain stimulation on walking and balance ability in Parkinson's patients: A systematic review and meta-analysis

Objective

To investigate and contrast the effects of non-invasive brain stimulation (NIBS), including repeated transcranial magnetic stimulation (rTMS) and transcranial direct current stimulation (tDCS), on walking and balance ability in patients with Parkinson's disease (PD).

Methods

The PubMed, Embase, Medline, Cochrane, CNKI, and Chinese WanFang databases were searched up to June 2022. Quality assessment was performed using the Cochrane Collaboration's risk-of-bias guidelines, and the standardized mean differences (SMD) or mean differences (MD) for each outcome were calculated.

Results

Among 32 eligible studies, including 1,586 participants were analyzed in this meta-analysis. The results of the meta-analysis showed that NIBS was effective in improving UPDRS-III scores (MD = -2.07; 95% CI, -2.62 to -1.53; P < 0.00001; I ² = 6%) and variables associated with the ability of walk such as step width (SMD = 0.35; 95% CI, 0.16-0.55; P = 0.0005; I ² = 38%), cadence (SMD = 0.3; 95% CI, 0.05 to 0.55; P = 0.02; I ² = 25%), and 6MWT (MD = 62.86; 95% CI, 39.43-86.29; P < 0.00001; I ² = 0%). In subgroup analyses across intervention types, UPDRS-III scores (rTMS: MD = -2.54; 95% CI, -3.16 to -1.92; P < 0.00001; I ² = 0%; tDCS: MD = -1.20; 95% CI, -1.99 to -0.40; P = 0.003; I ² = 0%) and TUGT time (rTMS: MD = -4.11; 95% CI, -4.74 to -3.47; P < 0.00001; I ² = 0%; tDCS: MD = -0.84; 95% CI, -1.48 to -0.21; P = 0.009; I ² = 0%) significantly improved. Moreover, our results also showed that compared to tDCS, rTMS was more significant in improving UPDRS-III scores and TUGT time (p < 0.05).

Conclusion

NIBS benefits some walking ability variables but not balance ability in 36 patients with PD. The rTMS significantly improved UPDRS-III scores and TUGT time compared to tDCS. Further studies are needed to determine the optimal protocol and to illuminate effects based on the ideal target brain regions, stimulation intensity, timing, and type of intervention.

Systematic review registration

http://www.crd.york.ac.uk/PROSPERO/, identifier CRD42022350782.

Psychiatric Comorbidities Affect the Hospitalization Course of Parkinson's Disease Patients: A Cross-Sectional Inpatient Study

Objectives

We aim to delineate the differences in demographic characteristics and hospitalization outcomes including the severity of illness, hospitalization length of stay (LOS) and cost, utilization of deep brain stimulation (DBS), and disposition in Parkinson’s disease (PD) inpatients with psychiatric comorbidities versus without psychiatric comorbidities.

Methods

We conducted a cross-sectional study using the Nationwide Inpatient Sample (NIS), included 56,844 PD inpatients (age ≥40 years), and subdivided them by inpatients into those without psychiatric comorbidities (N = 38,629) and with psychiatric comorbidities (N = 18,471). We compared the distributions of demographic characteristics and hospitalization outcomes (severity of illness, utilization ofDBS, and disposition) by performing Pearson’s chi-square test, and we measured the differences in continuous variables (i.e., age, LOS, and cost) by using the independent samples t-test. 

Results

A significantly higher proportion of PD inpatients with psychiatric comorbidities were female (44.4%) and white (83%) and had a moderate loss of functioning (48.8%) compared to those without psychiatric comorbidities. PD inpatients with psychiatric comorbidities had an increased mean LOS (4.7 days vs. 3.7 days, P <0.001) but a lower mean cost ($37,445 vs. $ 41,957, P <0.001). Also, there was a significantly lower utilization of DBS in PD inpatients with psychiatric comorbidities (19.2% vs. 26.9%, P <0.001) compared to those without psychiatric comorbidities, and an adverse disposition of transfer to a skilled nursing facility/intermediate care facility (47.1% vs. 39.6%, P <0.001) compared to PD inpatients without psychiatric comorbidities.

Conclusion

Although PD patients with psychiatric comorbidities had a moderate loss of functioning, there was significant underutilization of DBS. Meanwhile, psychiatric comorbidities among PD patients led to increased LOS and transfer to skilled facilities.

Transcranial direct current stimulation provides no clinically important benefits over walking training for improving walking in Parkinson's disease: a systematic review

QUESTIONS

Does walking training combined with transcranial direct current stimulation (tDCS) improve walking (ie, speed, cadence and step length) and reduce falls and freezing, compared with no/sham intervention, in people with Parkinson's disease? Is walking training combined with tDCS superior to walking training alone? Are any benefits carried over to social participation and/or maintained beyond the intervention period?

DESIGN

A systematic review with meta-analyses of randomised clinical trials.

PARTICIPANTS

Ambulatory adults with a clinical diagnosis of Parkinson's disease.

INTERVENTION

tDCS combined with walking training.

OUTCOME MEASURES

Primary outcomes were walking speed, cadence and step length. Secondary outcomes were number of falls, fear of falling, freezing of gait and social participation.

RESULTS

Five trials involving 117 participants were included. The mean PEDro score of the included trials was 8 out of 10. Participants undertook training for 30 to 60 minutes, two to three times per week, on average for 4 weeks. Moderate-quality evidence indicated that the addition of tDCS to walking training produced negligible additional benefit over the effect of walking training alone on walking speed (MD -0.01 m/s, 95% CI -0.05 to 0.04), step length (MD 1.2 cm, 95% CI -1.2 to 3.5) or cadence (MD -3 steps/minute, 95% CI -6 to 1). No evidence was identified with which to estimate the effect of the addition of tDCS to walking training on freezing of gait, falls and social participation.

CONCLUSION

The addition of tDCS to walking training provided no clinically important benefits on walking in ambulatory people with Parkinson's disease.

REGISTRATION

PROSPERO CRD42020162908.

The Queensland Parkinson's Project: An Overview of 20 Years of Mortality from Parkinson's Disease

OBJECTIVE

The consensus is that life expectancy for individuals with Parkinson's disease (PD) is reduced, but estimations vary. We aimed to provide an overview of 20 years of mortality and risk factor data from the Queensland Parkinson's Project.

METHODS

The analysis included 1,334 PD and 1,127 control participants. Preliminary analysis of baseline characteristics (sex, age at onset, family history, smoking status, pesticide exposure, depression and neurosurgery) was conducted, and Kaplan-Meier curves were generated for each potential risk factor. Standardized mortality ratios (SMRs) were calculated comparing this cohort to the general Australian population. Cox proportional hazards regression modeling was used to analyze potential predictors of mortality.

RESULTS

In total, 625 (46.8%) PD and 237 (21.0%) control participants were deceased. Mean disease duration until death was 15.3 ± 7.84 years. Average ages at death were 78.0 ± 7.4 years and 80.4 ± 8.4 years for the deceased PD and control participants, respectively. Mortality was significantly increased for PD in general {SMR = 2.75 [95% confidence interval (CI): 2.53-2.96]; p = 0.001}. SMRs were slightly higher for women and those with an age of onset before 60 years. Multivariate analysis showed that deep brain stimulation (DBS) treatment was associated with lower mortality [hazard ratio (HR) = 0.76; 95% CI: 0.59-0.98], while occasional pesticide exposure increased mortality risk (HR = 1.48; 95% CI: 1.17-1.88). Family history of PD, smoking and depression were not independent predictors of mortality.

CONCLUSION

Mortality in PD is increased. Sex, age at onset and occasional pesticide exposure were independent determinants of increased mortality, while DBS treatment was associated with reduced mortality.

Pharmacological Treatment of Early Motor Manifestations of Parkinson Disease (PD)

Parkinson disease (PD), as a slowly progressive neurodegenerative disorder, undergoes six neuropathological stages. The earliest clinical manifestation presents in the middle stage of the disorder pathologically, when 50% or more of the dopaminergic neurons have degenerated in the substantia nigra. This discrepancy between the early stage clinically and that pathologically has, in part, spurred the debate as to when it is best to initiate symptomatic therapy. The most well-studied monotherapeutic agents for PD in its early course include levodopa (the cornerstone of PD therapy), dopamine agonists, and monoamine oxidase inhibitors (MAOIs). With several options for initiating pharmacologic therapy, along with the heterogenous presentation of the disorder, an individualized approach is warranted. Careful deliberation must be done to optimize risk reduction while providing effective symptom control, taking the chronological age, comorbidities, social and financial disposition, work status, and both immediate- and long-term goals into consideration. Generally, treatment can be delayed in patients with mild symptoms and minimal functional impairment at any age. If treatment must be initiated, dopamine agonists and monoamine oxidase type B inhibitors can be used, especially in younger patients with milder disease. However, for older patients, those with moderate to severe PD symptoms, regardless of age, or for patients with greater comorbidities, levodopa generally remains the better choice. Eventually, regardless of initial therapy, studies have shown that most will eventually require levodopa therapy when symptoms become more disabling.

The Effect of Human Umbilical Cord Mesenchymal Stromal Cells in Protection of Dopaminergic Neurons from Apoptosis by Reducing Oxidative Stress in the Early Stage of a 6-OHDA-Induced Parkinson's Disease Model

Oxidative stress is an important cause of dopaminergic (DA) neuron apoptosis in Parkinson’s disease (PD). Mesenchymal stromal cells (MSCs) possess antioxidative features. In this study, we investigated whether MSCs could reduce oxidative stress and protect DA neurons from apoptosis by intravenous (I.V.) injection in the early stage of a 6-hydroxydopamine (6-OHDA)-induced PD model. MSCs were injected into the tail vein of mice, and behavioral tests, immunofluorescence staining, western blot, and oxidative stress levels were assessed at different time points. After 6-OHDA exposure, DA neuron apoptosis was detected, together with severe oxidative stress in brain and periphery. Compared with the non-transplanted sham controls, motor function in the 6-OHDA-lesioned group after I.V. injection of MSCs was significantly improved, and the levels of DA neuron apoptosis and oxidative stress decreased. The results demonstrate that MSCs can rescue DA neurons from ongoing apoptosis by reducing oxidative stress, and provide insights on developing new therapeutic strategies to offset the degenerative process of PD.

Mortality and cause of death in South Korean patients with Parkinson's disease: a longitudinal follow-up study using a national sample cohort

OBJECTIVE

The incidence rate of Parkinson's disease (PD) is growing rapidly owing to the ageing population. We investigated the mortality rates and causes of death in South Korean patients with PD.

DESIGN

We investigated a national cohort using the nationwide insurance database.

SETTING

Korean Health Insurance Review and Assessment Service-National Sample Cohort database.

PARTICIPANTS

We included 3510 participants ≥60 years of age who were diagnosed with PD between 2002 and 2013, as well as 14 040 matched controls.

INTERVENTIONS

None PRIMARY AND SECONDARY OUTCOME MEASURES: A stratified Cox proportional hazards model was used to evaluate patients with PD who were matched 1:4 with non-PD control subjects adjusted for age, sex, income and region of residence. The causes of death were grouped into 12 classifications.

RESULTS

The adjusted HR for mortality in the PD group was 2.09 (95% CI 1.94 to 2.24, p<0.001). Subgroup analysis according to age (<70 years, 70-79 years, and ≥80 years) and sex revealed that patients with PD showed higher adjusted HRs for mortality across all subgroups. Mortalities caused by metabolic, mental, neurologic, circulatory, respiratory, and genitourinary diseases, as well as trauma, were more common in the PD group than in the control group, with the highest OR observed in patients with neurologic disease.

CONCLUSIONS

We demonstrated that PD in South Korean patients ≥60 years of age was associated with increased mortality in both sexes regardless of age.

Depression in Parkinson's disease: A case-control study

Background

To evaluate the association between Parkinson’s disease (PD) prognosis and the patient’s onset of depression.

Methods

A total of 353 patients with newly-diagnosed PD and a history of depression were enrolled. On the basis of the onset of depression before or after PD diagnosis, we divided participants into PD patients with pre- or post-diagnostic depression. Cox’s regression analysis was used to detect risks between the onset of depression and outcomes (including death, accidental injury, dementia, and aspiration pneumonia). The association between the onset of depression and levodopa equivalent dosage (LED) and cumulative equivalent dosage of antidepressants were assessed.

Results

PD patients with post-diagnostic depression were associated with significantly higher risks of dementia (adjusted HR = 2·01, p = 0·015), and were older (58·5 ± 17·7 vs. 53·7 ± 18·6, p = 0·020) at the time of PD diagnosis than PD patients with pre-diagnostic depression. The higher incident rate of accidental injury was also noted in PD patients with post-diagnostic depression (48·1 vs. 31·3/1000 person-years, HR = 1·60, p = 0·041), but no statistical significance was observed in the adjusted hazard ratio (HR) (HR = 1·52, p = 0·069). Otherwise, mortality, motor condition and severity of depression revealed no significant difference between PD patients with pre-diagnostic and post-diagnostic depression.

Conclusion

PD patients with post-diagnostic depression had higher incidence of dementia, implying different onset time of depression could be associated with different subtypes and spreading routes which should be examined in follow-up studies.

Parkinson's Disease and development of levodopa induced motor complications: Influence of baseline features and first medical approach

Background

The introduction of levodopa in clinical practice represents a hallmark in the treatment of the neurodegenerative disease, Parkinson's Disease. However, levodopa induced motor complications, namely dyskinesias and motor fluctuations, develop in the majority of Parkinson's Disease patients.

Objective

to identify which Parkinson's Disease's, patient's and therapeutics' initial features are more associated with dyskinesias or motor fluctuations development.

Methods

Patients with diagnosed Parkinson's Disease attending neurology outpatient clinic at Centro Hospitalar São João were selected. For this observational study, data was retrospectively collected from patient's clinical records. A survival analysis model with univariate and multivariate regression analysis was used.

Results

87 patients with a mean of 72 ± 9.7 years were included. After a median follow-up of 6 (range 1-17) years, 35.6% patients developed dyskinesias; and with a median of 5 (range 1-16) years, 32.2% developed motor fluctuations. After multivariate analysis, the akinesia/rigidity subtype was found to have a higher risk of dyskinesias and motor fluctuations development. Age of onset ≤50 years was associated with motor fluctuations development.

Conclusion

In conclusion, our results suggest that Parkinson's Disease patients' initial characteristics, such as subtype or age of onset, are independently associated with the development of motor complications.

Premotor Symptoms as Predictors of Outcome in Parkinsons Disease: A Case-Control Study

Background

To evaluate the association between the premotor symptoms and the prognosis of PD.

Methods

A total of 1213 patients who were diagnosed of PD from January 2001 to December 2008 were selected from the Taiwan’s National Health Insurance Research Database. Patients were traced back to determine the presence of premotor symptoms, including rapid eye movement sleep behavior disorder (RBD), depression, and constipation. Cox’s regression analysis was used to detect the risks between the occurrence of premotor symptoms and the outcome (including death, psychosis, accidental injury, dementia and aspiration pneumonia). In addition, the association between premotor symptoms and levodopa equivalent dosage (LED) was examined.

Results

Higher occurrence of death, dementia and aspiration pneumonia were identified in PD patients with premotor symptoms than without premotor symptoms (HR 1·69, 95% CI 1·34–2·14, p <0·001 for death; HR 1·63, 95% CI 1·20–2·22, p = 0·002 for dementia; HR 2·45, 95% CI 1·42–4·21, p = 0·001 for aspiration pneumonia). In a comorbidities-stratified analysis, PD patients with premotor symptoms showed significantly high risks of mortality and morbidity (dementia and aspiration pneumonia), especially in the absence of comorbidities. Independent predictors of mortality in PD were found to be higher age, male sex, constipation, RBD, RBD with constipation and depression, and diabetes. Furthermore, no significant differences of LED and subsequent accidental injury were noted between PD patient with or without premotor symptoms.

Conclusion

Premotor symptoms seem to be not merely risk factors, but also prognostic factors of PD.

Clinical and Epidemiological Factors Associated with Mortality in Parkinson's Disease in a Brazilian Cohort

Background. Prognosis of PD is variable. Most studies show higher mortality rates in PD patients compared to the general population. Clinical and epidemiologic factors predicting mortality are poorly understood. Methods. Clinical and epidemiologic features including patient history and physical, functional, and cognitive scores were collected from a hospital-based cohort of PD patients using standardized protocols and clinical scales. Data on comorbidities and mortality were collected on follow-up. Results. During a mean follow-up of 4.71 years (range 1–10), 43 (20.9%) of the 206 patients died. Those who died had higher mean age at disease onset than those still alive at the last follow-up (67.7 years versus 56.3 years; p < 0.01). In the univariate analysis, age at baseline was associated with decreased survival. In the adjusted Cox proportional hazards model, age at disease onset and race/ethnicity were predictors of mortality. Conclusions. Late age at disease onset and advanced chronological age are associated with decreased survival. Comorbidities and PD characteristics were not associated with decreased survival in our sample. Race/ethnicity was found in our study to be associated with increased hazard of mortality. Our findings indicate the importance of studying survival among different populations of PD patients.

14-3-3 Proteins regulate mutant LRRK2 kinase activity and neurite shortening

Mutations in leucine-rich repeat kinase 2 (LRRK2) are the most common known cause of inherited Parkinson's disease (PD), and LRRK2 is a risk factor for idiopathic PD. How LRRK2 function is regulated is not well understood. Recently, the highly conserved 14-3-3 proteins, which play a key role in many cellular functions including cell death, have been shown to interact with LRRK2. In this study, we investigated whether 14-3-3s can regulate mutant LRRK2-induced neurite shortening and kinase activity. In the presence of 14-3-3θ overexpression, neurite length of primary neurons from BAC transgenic G2019S-LRRK2 mice returned back to wild-type levels. Similarly, 14-3-3θ overexpression reversed neurite shortening in neuronal cultures from BAC transgenic R1441G-LRRK2 mice. Conversely, inhibition of 14-3-3s by the pan-14-3-3 inhibitor difopein or dominant-negative 14-3-3θ further reduced neurite length in G2019S-LRRK2 cultures. Since G2019S-LRRK2 toxicity is likely mediated through increased kinase activity, we examined 14-3-3θ's effects on LRRK2 kinase activity. 14-3-3θ overexpression reduced the kinase activity of G2019S-LRRK2, while difopein promoted the kinase activity of G2019S-LRRK2. The ability of 14-3-3θ to reduce LRRK2 kinase activity required direct binding of 14-3-3θ with LRRK2. The potentiation of neurite shortening by difopein in G2019S-LRRK2 neurons was reversed by LRRK2 kinase inhibitors. Taken together, we conclude that 14-3-3θ can regulate LRRK2 and reduce the toxicity of mutant LRRK2 through a reduction of kinase activity.

An evidence-based approach to identify aging-related genes in Caenorhabditis elegans

Background

Extensive studies have been carried out on Caenorhabditis elegans as a model organism to elucidate mechanisms of aging and the effects of perturbing known aging-related genes on lifespan and behavior. This research has generated large amounts of experimental data that is increasingly difficult to integrate and analyze with existing databases and domain knowledge. To address this challenge, we demonstrate a scalable and effective approach for automatic evidence gathering and evaluation that leverages existing experimental data and literature-curated facts to identify genes involved in aging and lifespan regulation in C. elegans.

Results

We developed a semantic knowledge base for aging by integrating data about C. elegans genes from WormBase with data about 2005 human and model organism genes from GenAge and 149 genes from GenDR, and with the Bio2RDF network of linked data for the life sciences. Using HyQue (a Semantic Web tool for hypothesis-based querying and evaluation) to interrogate this knowledge base, we examined 48,231 C. elegans genes for their role in modulating lifespan and aging. HyQue identified 24 novel but well-supported candidate aging-related genes for further experimental validation.

Conclusions

We use semantic technologies to discover candidate aging genes whose effects on lifespan are not yet well understood. Our customized HyQue system, the aging research knowledge base it operates over, and HyQue evaluations of all C. elegans genes are freely available at http://hyque.semanticscience.org.

Electronic supplementary material

The online version of this article (doi:10.1186/s12859-015-0469-4) contains supplementary material, which is available to authorized users.