Secondary neurodegeneration following Stroke: what can blood biomarkers tell us?

Manual assessment of cylinder rearing behavior is more sensitive than automated gait evaluations in young, male mice post-stroke of the forepaw somatosensory cortex

BACKGROUND

Stroke is a leading cause of long-term adult disability. Behavioral testing with animal stroke models, which offers a way to evaluate the effectiveness of new interventions, currently relies on methods that are time- and labor-intensive. Automated behavioral assessments of locomotion and gait have been proposed as an alternative, but it is currently unknown whether they are sensitive enough to assess behavioral deficits following stroke of the forepaw somatosensory cortex. The purpose of this study was to compare a validated, manually assessed behavioral test, cylinder rearing (a measure of forepaw asymmetry during exploration), with automated behavior tests of locomotion in a rodent photothrombotic stroke model.

METHODS

We induced a focal photothrombotic stroke in young (12-16 week old) male mice over the left forepaw somatosensory cortex, conducted behavioral testing at acute (48 h) and sub-acute (4 weeks) time points post-stroke, and then correlated behavior deficits to histological measures.

RESULTS

Three automated behavioral tests were used in comparison to cylinder rearing: CatWalk (spontaneous gait), DigiGait (forced treadmill locomotion), and open field (a measure of general locomotor activity). Cylinder rearing testing showed significant forepaw asymmetry between stroke and sham groups acutely and sub-acutely after stroke. Catwalk, DigiGait, and open field tests showed no significant differences between groups. When correlating behavior to histological measures of stroke, the presence of secondary thalamic injury (STI) was associated with forepaw asymmetry on cylinder rearing.

CONCLUSIONS

These findings illustrate the need to find alternative automated behavioral measures for mouse photothrombotic stroke of the forepaw somatosensory cortex.

Proteinopathies and the Neurodegenerative Aftermath of Stroke: Potential Biomarkers and Treatment Targets

Stroke remains a predominant cause of death and long-term disability among adults worldwide. Emerging evidence suggests that proteinopathies, characterized by the aggregation and accumulation of misfolded proteins, may play a significant role in the aftermath of stroke and the progression of neurodegenerative disorders. In this review, we explore preclinical and clinical research on key proteinopathies associated with stroke, including tau, Aβ (amyloid-β), TDP-43 (TAR DNA-binding protein 43), α-synuclein, and UCH-L1 (ubiquitin C-terminal hydrolase-L1). We focus on their potential as biomarkers for recovery management and as novel treatment targets that may enhance neuronal repair and mitigate secondary neurodegeneration. The involvement of these proteinopathies in various aspects of stroke, including neuroinflammation, oxidative stress, neuronal damage, and vascular dysfunction, underscores their potential. However, further investigations are essential to validate the clinical utility of these biomarkers, elucidate the mechanisms connecting proteinopathies to poststroke neurodegeneration, and develop targeted interventions. Identifying specific protein signatures associated with stroke outcomes could facilitate the advancement of precision medicine tailored to individual patient needs, significantly enhancing the quality of life for stroke survivors.

Association that Neuroimaging and Clinical Measures Have with Change in Arm Impairment in a Phase 3 Stroke Recovery Trial

OBJECTIVE

Vagus nerve stimulation (VNS) paired with rehabilitation therapy improved motor status compared to rehabilitation alone in the phase III VNS-REHAB stroke trial, but treatment response was variable and not associated with any clinical measures acquired at baseline, such as age or side of paresis. We hypothesized that neuroimaging measures would be associated with treatment-related gains, examining performance of regional injury measures versus global brain health measures in parallel with clinical measures.

METHODS

Baseline magnetic resonance imaging (MRI) scans in the VNS-REHAB trial were used to derive regional injury measures (extent of injury to corticospinal tract, the primary regional measure; plus extent of injury to precentral gyrus and postcentral gyrus; lesion volume; and lesion topography) and global brain health measures (degree of white matter hyperintensities, the primary global brain measure; plus volumes of cerebrospinal fluid, cortical gray matter, white matter, each thalamus, and total brain). Eight clinical measures assessed at baseline were also evaluated (treatment group, age, race, gender, paretic side, pre-stroke dominant hand, time since stroke, and baseline Fugl-Meyer upper extremity score). Bivariate analyses compared each measure with the primary trial end point (change in Fugl-Meyer upper extremity score from baseline to end of 6 weeks of treatment) across all subjects, with secondary analyses examining trial groups separately.

RESULTS

MRIs were available from 80 patients (age = 59.8 ± 9.5 years, 29 women). Across all patients, less white matter hyperintensities (r = -0.25, p = 0.028) at baseline was associated with larger Fugl-Meyer score change. In the VNS group, less white matter hyperintensities (r = -0.37, p = 0.018) and larger ipsilesional thalamus volume (r = 0.33, p = 0.046) were each associated with larger Fugl-Meyer score change. Analysis of covariance (ANCOVA) analyses tested the interaction that each baseline measure had with treatment group and found that the model examining white matter hyperintensities had a significant interaction term, indicating 2.3 less change in Fugl-Meyer Upper Extremity (FM-UE) points in the VNS group relative to the control group for each point increase in modified Fazekas scale.

INTERPRETATION

Neuroimaging measures are associated with extent of gains on the primary endpoint of a phase III stroke recovery trial. Among the neuroimaging measures examined, a measure of global brain health (extent of white matter hyperintensities) was better at explaining the change in arm impairment as compared with measures of regional injury; this was true when examining all study subjects as well as only those in the VNS group and is consistent with the global mechanism of action that VNS has throughout the cerebrum. Future studies can evaluate additional measures that further predict response to VNS therapy. The current findings suggest that individual patient neuroimaging results may be useful for a personalized medicine approach to stroke recovery therapeutics. ANN NEUROL 2025;97:709-719.

Vitamin K Properties in Stroke and Alzheimer's Disease: A Janus Bifrons in Protection and Prevention

Vitamin K is essential for many physiological processes, including coagulation, bone metabolism, tissue calcification, and antioxidant activity. Vitamin K vitamers are represented by lipophilic compounds with similar chemical structure (i.e., phylloquinone (vitamin K1) and menaquinone (vitamin K2)). Vitamin K deficiency can affect coagulation and vascular calcification, increasing the risk of hemorrhages, atherosclerosis, cerebrovascular diseases, and neurodegeneration. Recently, several studies have hypothesized a possible dual role of vitamin K vitamers in benefiting both vascular and cerebral health, e.g., by sphingolipids biosynthesis or ferroptosis inhibition. The aim of this narrative review is to deepen the understanding of biological activities of vitamin K and its possible dual protective/preventive actions in neurovascular and degenerative conditions, e.g., stroke and dementia. Given the difficulties related to hemorrhagic risk entailed in the prevention of strokes, the function of vitamin K antagonists is also investigated. Finally, we track the development of a clinical concept for a future preventive strategy and innovative use of vitamin K as a supplement to counteract neurovascular and pathological processes, focusing in particular on stroke and dementia.

Unravelling neuroregenerative and neuroprotective roles of Wnt/β-catenin pathway in ischemic stroke: Insights into molecular mechanisms

Stroke is a serious condition often resulting in mortality or long-term disability, causing cognitive, memory, and motor impairments. A reduction in cerebral blood flow below critical levels defines the ischemic core and penumbra: the core undergoes irreversible damage, while the penumbra remains viable but functionally impaired. This functional impairment activates complex cell signaling pathways that determine cell survival or death, making the penumbra a key target for therapeutic interventions to prevent further damage. The Wnt/β-catenin (WβC) signaling pathway has emerged as a potential neuroprotective mechanism, promoting neurogenesis, angiogenesis, neuronal connectivity, and maintaining blood-brain barrier integrity after stroke. Activation of the WβC pathway also mitigates oxidative stress, inflammation, and apoptosis in ischemic regions, enhancing its neuroprotective effects. However, the overexpression of GSK3β and DKK1, or the presence of their agonists, can counteract these benefits. This review explores the therapeutic potential of WβC signaling, highlighting the effects of pharmacological modulation through antagonists, agonists, synthetic chemicals, natural products, stem cells, and macromolecules in preclinical models of ischemic stroke. While preclinical evidence supports the benefits of WβC activation, its role in human stroke requires further investigation. Additionally, the review discusses the potential adverse effects of prolonged WβC activation and suggests strategies to mitigate them. Overall, WβC signaling holds promise as a therapeutic target, offering insights into stroke pathophysiology and informing the development of novel treatment strategies.

Effects of Esketamine Combined with Dexmedetomidine on Early Postoperative Cognitive Function in Elderly Patients Undergoing Lumbar Spinal Surgery: A Double-Blind Randomized Controlled Clinical Trial

Background

Postoperative cognitive dysfunction (POCD) is a common complication after surgery in elderly patients, and its prevalence can be up to 25.6% at one week after noncardiac surgery. This study mainly evaluates the combined effects of esketamine and dexmedetomidine on the incidence of POCD in elderly patients undergoing lumbar spine surgery and explores the underlying mechanisms.

Methods

A total of 162 elderly patients undergoing lumbar spine surgery were randomized into three groups: esketamine combined with dexmedetomidine group (ED group), esketamine group (E group), and dexmedetomidine group (D group). Primary outcome measures included the incidence of POCD on the first postoperative day. Secondary outcomes included the incidence of POCD on the third postoperative day, first postoperative day serum levels of neuron-specific enolase (NSE) and calcium-binding protein β (S100β), patient visual analog scale (VAS) scores at 2, 24, and 48 hours postoperatively, and the incidence of adverse events.

Results

The incidence of POCD on the first postoperative day was significantly lower in the ED group compared to the E group (P = 0.017), with no significant differences when compared to the D group (P = 0.064). The levels of serum NSE in patients in the ED group on the first postoperative day were significantly lower than those in E group and D group (ED group vs E group, P = 0.028; ED group vs D group, P = 0.048). The results for the S100β were similar to those for the NSE (ED group vs E group, P = 0.005; ED group vs D group, P = 0.011).

Conclusion

The combination of esketamine and dexmedetomidine effectively reduces the incidence of POCD on the first postoperative day in elderly patients undergoing lumbar spine surgery.

Biobanking, digital health and privacy: the choices of 1410 volunteers and neurological patients regarding limitations on use of data and biological samples, return of results and sharing

BACKGROUND

The growing diffusion of artificial intelligence, data science and digital health has highlighted the role of collection of data and biological samples, thus raising legal and ethical concerns regarding its use and dissemination. Further, the expansion of biobanking, from the basic collection of frozen specimens to the virtual biobanks of specimens and associated data that exist today, has given a revolutionary potential on healthcare systems, particularly in the field of neurological diseases, due to the inaccessibility of central nervous system and the need of non-invasive investigation approaches. Informed Consent (IC) is considered mandatory in all research studies and specimen collections, and must specifically take into account the ethical respect to the individuals to whom the used biological material and data belong.

METHODS

We evaluated the attitudes of patients with neurological diseases (NP) and healthy volunteers (HV) towards the donation of biological samples to a biobank for future research studies on neurological diseases, and limitations on the use of data, related to the requirements set by the General Data Protection Regulation (GDPR). The study involved a total of 1454 subjects, including 502 HVs and 952 NPs, recruited at Santa Lucia Foundation IRCCS, Rome, from 2020 to 2024.

RESULTS

We found that (i) almost all subjects agreed with the participation in biobanking (ii) and authorization to genetic studies (HV = 99.1%; NP = 98.3%); Regarding the return of results, (iii) we found a statistically significant difference between NP and HV, the latter preferring not to be informed of potential results (HV = 43%; NP = 11.3%; p < 0.0001); (iv) a small number limited the sharing inside European Union (EU) (HV = 4.6%; NP = 6.6%), whereas patients were more likely to refuse transfer outside EU (HV = 7.4%; NP = 10.7% p = 0.05); (v) nearly all patients agreed with the use of additional health data from EMR for research purposes (98.9%).

CONCLUSIONS

Consent for the donation of material for research purposes is crucial for biobanking and biomedical research studies that use biological material of human origin. Here, we have shown that choices regarding participation in a neurological biobank can be different between HVs and NPs, even if the benefit for research and scientific progress is recognized. NP have a strong interest in being informed of possible results but limit sharing of samples, highlighting a perception of greater individual or relative benefit, while HV prefer a wide dissemination and sharing of data but not to have the return of the results, favoring a possible benefit for society and knowledge. The results underline the need to carefully manage biological material and data collected in biobanks, in compliance with the GDPR and the specific requests of donors.

Clinical characteristics of post-stroke basal ganglia aphasia and the study of language-related white matter tracts based on diffusion spectrum imaging

BACKGROUND

Stroke often damages the basal ganglia, leading to atypical and transient aphasia, indicating that post-stroke basal ganglia aphasia (PSBGA) may be related to different anatomical structural damage and functional remodeling rehabilitation mechanisms. The basal ganglia contain dense white matter tracts (WMTs). Hence, damage to the functional tract may be an essential anatomical structural basis for the development of PSBGA.

METHODS

We first analyzed the clinical characteristics of PSBGA in 28 patients and 15 healthy controls (HCs) using the Western Aphasia Battery and neuropsychological test batteries. Moreover, we investigated white matter injury during the acute stage using diffusion magnetic resonance imaging scans for differential tractography. Finally, we used multiple regression models in correlation tractography to analyze the relationship between various language functions and quantitative anisotropy (QA) of WMTs.

RESULTS

Compared with HCs, patients with PSBGA showed lower scores for fluency, comprehension (auditory word recognition and sequential commands), naming (object naming and word fluency), reading comprehension of sentences, Mini-Mental State Examination, and Montreal Cognitive Assessment, along with increased scores in Hamilton Anxiety Scale-17 and Hamilton Depression Scale-17 within 7 days after stroke onset (P < 0.05). Differential tractography revealed that patients with PSBGA had damaged fibers, including in the body fibers of the corpus callosum, left cingulum bundles, left parietal aslant tracts, bilateral superior longitudinal fasciculus II, bilateral thalamic radiation tracts, left fornix, corpus callosum tapetum, and forceps major, compared with HCs (FDR < 0.02). Correlation tractography highlighted that better comprehension was correlated with a higher QA of the left inferior fronto-occipital fasciculus (IFOF), corpus callosum forceps minor, and left extreme capsule (FDR < 0.0083). Naming was positively associated with the QA of the left IFOF, forceps minor, left arcuate fasciculus, and uncinate fasciculus (UF) (FDR < 0.0083). Word fluency of naming was also positively associated with the QA of the forceps minor, left IFOF, and thalamic radiation tracts (FDR < 0.0083). Furthermore, reading was positively correlated with the QA of the forceps minor, left IFOF, and UF (FDR < 0.0083).

CONCLUSION

PSBGA is primarily characterized by significantly impaired word fluency of naming and preserved repetition abilities, as well as emotional and cognitive dysfunction. Damaged limbic pathways, dorsally located tracts in the left hemisphere, and left basal ganglia pathways are involved in PSBGA pathogenesis. The results of connectometry analysis further refine the current functional localization model of higher-order neural networks associated with language functions.

Brain neurotrophic factor BDNF: new data, functions and questions

The brain-derived neurotrophic factor (BDNF) is a key modulator of neurogenesis, synaptogenesis, neuroregeneration, and cell differentiation in the nervous system. Impaired BDNF functioning is a characteristic of various neurological diseases, such as Alzheimer’s disease, multiple sclerosis, and depressive disorders. There is recent evidence that patients with COVID-19 have reduced BDNF levels in the blood plasma. Furthermore, exogenous BDNF and its mimetics have demonstrated therapeutic potential. In this review, we systematized data of the BDNF gene structure, epigenetic and microRNA-mediated regulation of its expression, transcriptional variants of BDNF, and the effects of BDNF on neuronal and oligodendroglial differentiation. Further, we point out the gaps in the current knowledge about BDNF and propose experiments that can expand such knowledge and the range of possibilities for using BDNF in biomedicine. These include determining the expression pattern of all BDNF gene transcripts at different stages of differentiation and in different cell subpopulations and studying the role of receptor-independent BDNF signaling, circadian fluctuations in BDNF levels, and their role in physiological and pathophysiological conditions. Finally, for translational medicine, evaluating the effect of BDNF mimetics (including those immobilized on three-dimensional scaffolds for tissue engineering) on neuronal and oligodendroglial differentiation of pluripotent and polypotent cells and identifying molecular regulators of BDNF transcription, including small molecules and microRNAs capable of regulating BDNF gene expression, are crucial.