Neuroimaging, serum biomarkers, and patient characteristics as predictors of upper limb functioning 12 weeks after acute stroke: an observational, prospective study

OBJECTIVE

To evaluate the potential of neuroimaging, serum biomarkers, stroke etiology, and clinical characteristics as predictors of upper limb functioning 12 weeks after stroke.

METHODS

This was a prospective, observational study of patients (18-85 years-old) hospitalized due to acute ischemic stroke in the territory of the middle cerebral artery. Patients were hospitalized at a stroke rehabilitation center, where they underwent a standardized rehabilitation program. Clinical, imagiology, laboratory (biomarkers: C-reactive protein, D-dimer, and fibrinogen, and S100 calcium binding protein β [S100β]), and functionality assessments were conducted four different times: within 24 hours, and at 48 hours, 3 weeks, and 12 weeks after acute stroke.

RESULTS

Upper limb functioning at 12 weeks was significantly associated with Alberta Stroke Program Early CT Score (ASPECTS) score (OR:2.012 [CI:1.349-3.000]; P = 0.001) and S100β protein levels (OR:0.997 [CI:0.994-0.999]; P = 0.007). Advanced age was associated with poor upper limb functioning. S100β protein levels < 140.5 ng/L at 48 hours and ASPECTS scores ≥ 7.5 within 24 hours of admission predicted good hand functioning at 12 weeks. Upper limb functioning and general functioning were significantly correlated (P < 0.001), with strong negative correlations (all correlation coefficients ≤-0.586) for all comparisons.

CONCLUSION

ASPECTS score ≥ 8 within 24 hours and S100β protein < 140.5 ng/L at 48 hours predict better upper limb functioning, while advanced age predicts worse upper limb functioning 12 weeks after stroke.

S100β Protein as a Predictor of Poststroke Functional Outcome: A Prospective Study

BACKGROUND

Stroke is one of the leading causes of disability worldwide. Early prediction of poststroke disability using clinical models is of great interest, especially in the rehabilitation field. Although some biomarkers and neuroimaging techniques have shown potential predictive value, there are still insufficient data to support their clinical utility in predicting poststroke functional recovery. We aimed to assess the value of serum biomarkers (C-reactive protein [CRP], D-dimer, fibrinogen, and S100β protein) in predicting medium-term (12 weeks) functional outcome in patients with acute ischemic stroke.

METHODS

This is an observational, prospective study in a sample of patients hospitalized for ischemic stroke (N = 131). Peripheral blood levels of biomarkers of interest were determined at admission (CRP, D-dimer, and fibrinogen) or at 48 hours poststroke (S100β protein). Functional status was accessed at 48 hours and 12 weeks poststroke using the modified Rankin Scale (mRS).

RESULTS

S100β protein levels measured at 48 hours were significantly associated with mRS scores at 12 weeks (odds ratio = 1.005, 95% confidence interval [CI] [1.005-1.007]; P <.001). This association was not seen for the remaining biomarkers of interest. The S100β cutoff for poor functionality at 12 weeks was 140.5 ng/L or more (sensibility 83.8%; specificity 71.4%; area under the curve = .80, 95% CI [.722, .879]).

CONCLUSIONS

S100β levels in peripheral blood at 48 hours poststroke reflect acute stroke severity and predict functional outcome at 12 weeks with a cutoff value of 140.5 ng/dL. The value of S100β as predictor of functional recovery after stroke should be emphasized in further clinical research and clinical practice.

Cortisol plays a role in the high environmental ammonia associated suppression of the immune response in zebrafish

Exposure to high environmental ammonia (HEA) levels increases the vulnerability of fishes to parasitic, viral and bacterial diseases. We tested the hypothesis that elevated plasma cortisol levels play a role in the HEA-mediated immunosuppression in fishes. To this end, we tested the effect of exogenous cortisol treatment on the lipopolysaccharide (LPS)-induced immune response in zebrafish (Danio rerio). Also, to test whether glucocorticoid receptor (GR) signaling is involved in HEA-mediated immunosuppression, zebrafish were treated with mifepristone, a GR antagonist, and the LPS-induced immune response assessed after HEA exposure. We evaluated a panel of important immunity-related genes including interleukin 1β (il1b) and suppressor of cytokine signaling (socs-1a, 2, 3) and acute phase response genes [serum amyloid A (saa), transferrin (tfa), leukocyte cell-derived chemotaxin 2-like (lect2l), haptoglobin (hp), hepcidin (=hepatic anti-microbial peptide hamp), and complement component 3b (c3b)] by real-time quantitative PCR. Our results demonstrate that exogenous cortisol administration as well as elevated cortisol levels in response to HEA exposure modulate mRNA transcript levels of key mediators of the innate immune response in zebrafish. Mifepristone treatment reduced whole body cortisol levels and eliminated the HEA-mediated changes in transcript abundance of socs1a, il1b, as well as APR genes. Together, these results suggest that the HEA effect on the innate immune response is in part mediated by cortisol signaling, while the mode of action, including the receptors involved remains to be elucidated.

Fibroblasts of Machado Joseph Disease patients reveal autophagy impairment

Machado Joseph Disease (MJD) is the most frequent autosomal dominantly inherited cerebellar ataxia caused by the over-repetition of a CAG trinucleotide in the ATXN3 gene. This expansion translates into a polyglutamine tract within the ataxin-3 protein that confers a toxic gain-of-function to the mutant protein ataxin-3, contributing to protein misfolding and intracellular accumulation of aggregates and neuronal degeneration. Autophagy impairment has been shown to be one of the mechanisms that contribute for the MJD phenotype. Here we investigated whether this phenotype was present in patient-derived fibroblasts, a common somatic cell type used in the derivation of induced pluripotent stem cells and subsequent differentiation into neurons, for in vitro disease modeling. We generated and studied adult dermal fibroblasts from 5 MJD patients and 4 healthy individuals and we found that early passage MJD fibroblasts exhibited autophagy impairment with an underlying mechanism of decreased autophagosome production. The overexpression of beclin-1 on MJD fibroblasts reverted partially autophagy impairment by increasing the autophagic flux but failed to increase the levels of autophagosome production. Overall, our results provide a well-characterized MJD fibroblast resource for neurodegenerative disease research and contribute for the understanding of mutant ataxin-3 biology and its molecular consequences.

Tuberculosis screening in patients receiving biological therapy

AIM

Biological therapies are a risk factor for tuberculosis (TB). Portuguese recommendations recommend universal baseline screening for TB before starting biologics (2006) and annually thereafter if screened negative (2012 update). The gain with re-screening remains unknown. We aimed to i)identify the risk of latent TB infection at baseline screening among patients candidates to initiate biologics ii)present follow-up results for patients receiving different biological therapies and analyse intolerance or toxicity related to preventive therapy, conversions of immunodiagnostic tests under biological therapy and development of active TB.

METHODS

Patients screened for TB at a reference centre before starting biological therapy between 2008-2012 were identified. Medical files were retrospectively reviewed. Demographic data, screening and follow-up results and information on biological therapy were collected.

EXCLUSION CRITERIA

unavailable information on initiation of biological therapy.

RESULTS

183 patients were included in the study, with 115 starting biological therapy. The baseline screening was positive in 52(45,2%) patients - 50(96,2%) were proposed for preventive treatment (2 had abnormal liver enzymes). Mild hepatotoxicity occurred in 4(8%) patients without need to interrupt TB prophylaxis. No cases of active TB occurred during follow-up in patients with positive baseline screening. Among the 63(54,8%) patients who screened negative, 2(3,2%) developed active TB (under infliximab and adalimumab) more than one year after initiation of biologics. 26(41,3%) patients were re-screened at the TB centre. 5(19,2%) had tuberculin skin test (TST) conversion and one concomitantly undetermined IGRA. No IGRA conversions were observed. The follow-up period was 4,0 years. TB baseline screening's negative predictive value (NPV) was 96,8% (95%CI: 89,0% to 99.5%). A low rate of re-screening was observed.

CONCLUSION

The rate of latent TB at baseline screening was higher than expected. Preventive treatment was well tolerated. No patients with positive baseline screening developed active TB. Efforts should be made to raise awareness concerning the risk of TB exposure, specially considering that the active TB cases were compatible with new infection. The rate of re-screening suggests a low awareness regarding current recommendations Nation-wide studies are necessary to evaluate the efficacy of the re-screening strategy and to clarify what risk groups most benefit from it.

The inhibitory effect of environmental ammonia on Danio rerio LPS induced acute phase response

Ammonia is a toxic by-product of amino acid catabolism and a common environmental pollutant that has been associated with increased disease susceptibility in fish although the mechanism is not well understood. We addressed the hypothesis that elevated environmental ammonia acts by impairing the acute phase response (APR). Specifically, we determined the impact of sub-lethal acute (24 h) and chronic (14 d) ammonia exposure on acute phase protein gene expression in zebrafish (Danio rerio) in response to a challenge with bacterial lipopolysaccharide (LPS: i.p. 10 μg/g after 24h). A panel of LPS-responsive genes (SAA, HAMP, LECT2, Hp and IL1β) were identified and evaluated by real-time quantitative PCR. Ammonia was found to impair induction of SAA, HAMP and LECT2 by 50-90%. Both short (15 min, 1h and 24h) and long-term (14 days) exposure to high environmental ammonia concentrations significantly elevated whole-body cortisol levels compared with control fish. Our results reveal for the first time that exposure to high environmental levels of ammonia suppresses the innate immune response in fish. We hypothesize that high environmental ammonia-mediated elevation of cortisol levels in zebrafish may be playing a key role in this immunosuppression, while the mechanisms involved remains to be elucidated.

The role of the basal ganglia in implicit contextual learning: a study of Parkinson's disease

Implicit contextual learning refers to the ability to memorize contextual information from our environment. This contextual information can then be used to guide our attention to a specific location. Although the medial temporal lobe is important for this type of learning, the basal ganglia might also be involved considering its role in many implicit learning processes. In order to understand the role of the basal ganglia in this top-down process, a group of non-demented early-stage Parkinson's patients were tested with a contextual cueing task. In this visual search task, subjects have to quickly locate a target among a number of distractors. To test implicit contextual learning, some of the configurations are repeated during the experiment, resulting in faster responses. A significant interaction effect was found between Group and Configuration, indicating that the control subjects responded faster when the spatial context was repeated, whereas Parkinson's patients failed to do so. These results, showing that the contextual cueing effect was significantly different for the patients than for the controls, suggest an important role for the basal ganglia in implicit contextual learning, thus extending previous findings of medial temporal lobe involvement. The basal ganglia are therefore not only involved in implicit motor learning, but may also have a role in purely visual implicit learning.

[The prevalence of cerebrovascular stroke in Coimbra]

The purpose of this study was to assess the prevalence of strokes in a community-based on a sample of the population of the county of Coimbra in 1992 (139,000 inhabitants). The study was made with the collaboration of local general practitioners who randomly selected a sample of 950 individuals over 50 years of age. These individuals were screened for the presence of vascular risk factors and strokes in the past, and submitted to clinical and laboratory examinations. There were 86 persons with strokes (crude prevalence 8%: 10.2% male, 6.6% female) the diagnosis being confirmed by neurological examination or analysis of hospital registers. Hypertension was significantly more frequent in patients with strokes (56.8%). Other risk factors had no significant differences. The magnitude of disability associated with stroke was assessed according to the modified Rankin scale. About fifty percent had no significant disability or a slight disability and 20% were severely disabled.

Homovanillic acid in the cerebrospinal fluid of Parkinsonian patients

Determinations of CSF HVA before and after Probenecid administration were made in 41 patients with Parkinson’s disease. The means of HVA concentration were lower than those of controls but no correlation with clinical data was found. A negative correlation was demonstrated between post-probenecid HVA levels and subsequent score improvement with L-DOPA at 3,6 and 12 months. Post-probenecid HVA levels suggest that there are distinct forms of parkinsonism and could predict the response to L-DOPA therapy.