Updates in the Treatment of Post-Stroke Pain

A Novel Endoplasmic Reticulum-Targeted Metal-Organic Framework-Confined Ruthenium (Ru) Nanozyme Regulation of Oxidative Stress for Central Post-Stroke Pain

Central post-stroke pain (CPSP) is a chronic neuropathic pain caused by cerebrovascular lesion or disfunction after stroke. Convincing evidence suggest that excessive reactive oxygen species (ROS), generated matrix metalloproteinase (MMPs) and neuroinflammation are largely involved in the development of pain. In this study, an effective strategy is reported for treating pain hypersensitivity using an endoplasmic reticulum (ER)-targeted metal-organic framework (MOF)-confined ruthenium (Ru) nanozyme. The Ru MOF is coated with a p-dodecylbenzene sulfonamide (p-DBSN) modified liposome with endoplasmic reticulum-targeted function. The experimental results reveals that ROS, Emmprin, MMP-2, and MMP-9 are upregulated in the brain of CPSP mice, along with the elevated expression of inflammation markers such as TNF-α and IL-6. Compared to vehicle, one-time intravenous administration of ER-Ru MOF significantly reduces mechanical hypersensitivity after CPSP for three days. Overall, ER-Ru MOF system can inhibit oxidative stress in the brain tissues of CPSP model, reduce MMPs expression, and suppress neuroinflammation response-induced injury, resulting in satisfactory prevention and effective treatment of CPSP during a hemorrhagic stroke. The ER-Ru MOF is expected to be useful for the treatment of neurological diseases associated with the vicious activation of ROS, based on the generality of the approach used in this study.

Post-Stroke Neuropsychiatric Complications: Types, Pathogenesis, and Therapeutic Intervention

Almost all stroke survivors suffer physical disabilities and neuropsychiatric disturbances, which can be briefly divided into post-stroke neurological diseases and post-stroke psychiatric disorders. The former type mainly includes post-stroke pain, post-stroke epilepsy, and post-stroke dementia while the latter one includes post-stroke depression, post-stroke anxiety, post-stroke apathy and post-stroke fatigue. Multiple risk factors are related to these post-stroke neuropsychiatric complications, such as age, gender, lifestyle, stroke type, medication, lesion location, and comorbidities. Recent studies have revealed several critical mechanisms underlying these complications, namely inflammatory response, dysregulation of the hypothalamic pituitary adrenal axis, cholinergic dysfunction, reduced level of 5-hydroxytryptamine, glutamate-mediated excitotoxicity and mitochondrial dysfunction. Moreover, clinical efforts have successfully given birth to many practical pharmaceutic strategies, such as anti-inflammatory medications, acetylcholinesterase inhibitors, and selective serotonin reuptake inhibitors, as well as diverse rehabilitative modalities to help patients physically and mentally. However, the efficacy of these interventions is still under debate. Further investigations into these post-stroke neuropsychiatric complications, from both basic and clinical perspectives, are urgent for the development of effective treatment strategies.

Post-stroke Everything

PURPOSE OF REVIEW

This review aims at providing updates on selected post-stroke complications. We examined recent advances in diagnosing and treating the following post-stroke complications: cognitive impairment, epilepsy, depression, fatigue, tremors, dysphagia, and pain.

RECENT FINDINGS

Advances in understanding the mechanisms of post-stroke complications, in general, are needed despite advances made in understanding, treating, and preventing these complications. There are growing progresses in integrating new tools to diagnose post-stroke cognitive impairment. The potential role of acute stroke reperfusion treatment in post-stroke epilepsy and its impact on other stroke complications is getting more transparent. Post-stroke depression remains underestimated and new tools to diagnose depression after stroke are being developed. New promising pharmacological approaches to treating post-stroke pain are emerging. Tremors related to stroke are poorly understood and under-evaluated, while treatment towards post-stroke dysphagia has benefited from new non-pharmacological to pharmacological approaches.

CONCLUSIONS

An integrative approach to stroke complications and collaborations between providers across specialties are more likely to improve stroke outcomes.

Secondary headaches - red and green flags and their significance for diagnostics

A small percentage of patients suffer from a secondary headache syndrome. It is imperative that clinicians are able to differentiate primary headache syndromes from secondary headache syndromes, as failure to do so significantly worsens morbidity and mortality. Recent advances in our understanding of pathobiological mechanisms offer useful information on these enigmatic disorders. We now understand that the causes of secondary headache syndromes can vary significantly - these may be infectious, inflammatory, vascular, traumatic or structural in origin. A well-taken history and targeted physical examination coupled with appropriate investigations can enable these syndromes to be recognized consistently and thus allow their timely and appropriate treatment. Along with their epidemiology, some of their key characteristics shall thus be discussed in this review so as to aid the busy clinician at the bedside. Red flags including sudden onset, high pain intensity, pattern of change of a preexisting headache, focal neurological signs or seizure, systemic signs and precipitation by physical activity can guide the clinician to suspect a secondary headache. Importantly a preexisting headache is not an exclusion of a secondary headache - it might even be a predisposition in certain cases.

Neurotechnology for Pain

Neurotechnologies for treating pain rely on electrical stimulation of the central or peripheral nervous system to disrupt or block pain signaling and have been commercialized to treat a variety of pain conditions. While their adoption is accelerating, neurotechnologies are still frequently viewed as a last resort, after many other treatment options have been explored. We review the pain conditions commonly treated with electrical stimulation, as well as the specific neurotechnologies used for treating those conditions. We identify barriers to adoption, including a limited understanding of mechanisms of action, inconsistent efficacy across patients, and challenges related to selectivity of stimulation and off-target side effects. We describe design improvements that have recently been implemented, as well as some cutting-edge technologies that may address the limitations of existing neurotechnologies. Addressing these challenges will accelerate adoption and change neurotechnologies from last-line to first-line treatments for people living with chronic pain.

Spinal MCP-1 Contributes to Central Post-stroke Pain by Inducing Central Sensitization in Rats

Central post-stroke pain (CPSP) is a highly refractory form of central neuropathic pain that has been poorly studied mechanistically. Recent observations have emphasized the critical role of the spinal dorsal horn in CPSP. However, the underlying mechanisms remain unclear. In this study, rats were subjected to thalamic hemorrhage to investigate the role of spinal monocyte chemoattractant protein-1 (MCP-1) and C-C motif chemokine receptor 2 (CCR2) in the development of CPSP. Immunohistochemical staining and ELISA were used to assess the expression changes of c-Fos, Iba-1, GFAP, MCP-1, and CCR2 in the dorsal horn of the lumbar spinal cord following thalamic hemorrhage, and the involvement of spinal MCP-1 in CPSP was examined by performing intrathecal anti-MCP-1 mAb injection to neutralize the spinal extracellular MCP-1. We demonstrated that intra-thalamic collagenase microinjection induced persistent bilateral mechanical pain hypersensitivity and facilitated the spontaneous pain behaviors evoked by intraplantar bee venom injection. Accompanying CPSP, the expression of c-Fos, Iba-1, and GFAP in the lumbar spinal dorsal horn was significantly increased up to 28 days post-intra-thalamic collagenase microinjection. Intrathecal injection of minocycline and fluorocitrate dramatically reverses the bilateral mechanical pain hypersensitivity. Moreover, intra-thalamic collagenase microinjection dramatically induced the up-regulation of MCP-1 but had no effect on the expression of CCR2 in the bilateral lumbar spinal dorsal horn, and MCP-1 was primarily localized in the neuron. Intrathecal injection of anti-MCP-1 mAb was also able to reverse CPSP and reduce the expression of c-Fos, Iba-1, and GFAP in the lumbar spinal dorsal horn. These findings indicated that spinal MCP-1 contributes to CPSP by mediating the activation of spinal neurons and glial cells following thalamic hemorrhage stroke, which may provide insights into pharmacologic treatment for CPSP.

Stellate ganglion block ameliorated central post-stroke pain with comorbid anxiety and depression through inhibiting HIF-1α/NLRP3 signaling following thalamic hemorrhagic stroke

BACKGROUND

Central post-stroke pain (CPSP) is an intractable and disabling central neuropathic pain that severely affects patients' lives, well-being, and socialization abilities. However, CPSP has been poorly studied mechanistically and its treatment remains challenging. Here, we used a rat model of CPSP induced by thalamic hemorrhage to investigate its underlying mechanisms and the effect of stellate ganglion block (SGB) on CPSP and emotional comorbidities.

METHODS

Thalamic hemorrhage was produced by injecting collagenase IV into the ventral-posterolateral nucleus (VPL) of the right thalamus. The up-and-down method with von Frey hairs was used to measure the mechanical allodynia. Behavioral tests were carried out to examine depressive and anxiety-like behaviors including the open field test (OFT), elevated plus maze test (EPMT), novelty-suppressed feeding test (NSFT), and forced swim test (FST). The peri-thalamic lesion tissues were collected for immunofluorescence, western blotting, and enzyme-linked immunosorbent assay (ELISA). Genetic knockdown of thalamic hypoxia-inducible factor-1α (HIF-1α) and NOD-like receptor thermal protein domain associated protein 3 (NLRP3) with microinjection of HIF-1α siRNA and NLRP3 siRNA into the VPL of thalamus were performed 3 days before collagenase injection into the same regions. Microinjection of lificiguat (YC-1) and MCC950 into the VPL of thalamus were administrated 30 min before the collagenase injection in order to inhibited HIF-1α and NLRP3 pharmacologically. Repetitive right SGB was performed daily for 5 days and laser speckle contrast imaging (LSCI) was conducted to examine cerebral blood flow.

RESULTS

Thalamic hemorrhage caused persistent mechanical allodynia and anxiety- and depression-like behaviors. Accompanying the persistent mechanical allodynia, the expression of HIF-1α and NLRP3, as well as the activities of microglia and astrocytes in the peri-thalamic lesion sites, were significantly increased. Genetic knockdown of thalamic HIF-1α and NLRP3 significantly attenuated mechanical allodynia and anxiety- and depression-like behaviors following thalamic hemorrhage. Further studies revealed that intra-thalamic injection of YC-1, or MCC950 significantly suppressed the activation of microglia and astrocytes, the release of pro-inflammatory cytokines, the upregulation of malondialdehyde (MDA), and the downregulation of superoxide dismutase (SOD), as well as mechanical allodynia and anxiety- and depression-like behaviors following thalamic hemorrhage. In addition, repetitive ipsilateral SGB significantly restored the upregulated HIF-1α/NLRP3 signaling and the hyperactivated microglia and astrocytes following thalamic hemorrhage. The enhanced expression of pro-inflammatory cytokines and the oxidative stress in the peri-thalamic lesion sites were also reversed by SGB. Moreover, LSCI showed that repetitive SGB significantly increased cerebral blood flow following thalamic hemorrhage. Most strikingly, SGB not only prevented, but also reversed the development of mechanical allodynia and anxiety- and depression-like behaviors induced by thalamic hemorrhage. However, pharmacological activation of thalamic HIF-1α and NLRP3 with specific agonists significantly eliminated the therapeutic effects of SGB on mechanical allodynia and anxiety- and depression-like behaviors following thalamic hemorrhage.

CONCLUSION

This study demonstrated for the first time that SGB could improve CPSP with comorbid anxiety and depression by increasing cerebral blood flow and inhibiting HIF-1α/NLRP3 inflammatory signaling.

Bibliometric Analysis of Post-Stroke Pain Research Published from 2012 to 2021

Background and Purpose

Pain is one of the most common symptoms in patients after stroke. It is a distressing experience that affects patients' quality of life, and it is highly prevalent in clinical practice. The pathogenesis mechanisms of PSP are not so clear, and there is currently a lack of effective medical treatments, hence it is necessary to establish a sufficient understanding of this disease. Limited number of studies have applied bibliometric methods to systematically analyze studies on post-stroke pain. This study aimed to systematically analyze scientific studies conducted worldwide on post-stroke pain from 2012 to 2021 to evaluate global trends in this field using a bibliometric analysis.

Methods

Publications related to post-stroke pain from 2012 to 2021 were obtained from the Web of Science Core Collection database. Bibliometrics Biblioshiny R-package software was used to analyze the relationship of publication year with country, institution, journals, authors, and keywords and to generate variant visual maps to show annual publications, most relevant countries, authors, sources, keywords, and top-cited articles.

Results

In this study, 5484 papers met the inclusion criteria. The annual growth rate of publications was 5.13%. The USA had the highest number of publications (1381, 25.2%) and citations (36,395), and the University of Toronto had the highest number of papers (156, 2.8%). "Stroke", "management", "pain", "risk", "prevalence", "ischemic stroke", "risk factors", "disease", "diagnosis" and "therapy" are the top 10 keywords.

Conclusion

The global research interest regarding PSP has maintained growing over the past ten years. Both central post stroke pain and hemiplegic shoulder pain are the hottest research subjects. Further investigations are needed in order to reveal the mystery of the pathophysiologic mechanisms of CPSP, and high-quality well-designed trials of potential treatments of CPSP and HSP are also needed.

HEMODYNAMIC FEATURES IN THE PATIENTS AFTER STROKE SUFFERED FROM CHRONIC PAIN

OBJECTIVE

The aim: To study the hemodynamic parameters in patients with post-stroke pain syndromes.

PATIENTS AND METHODS

Materials and methods: We examined the hemodynamic parametrs of 74 patients who were treated at the Departments of General Neurology, Vascular Neurology and Pain Center in the Clinical Hospital «Feofania» State Administrative Department. Main group (44 patients) had stroke in anamnesis and chronic pain (headache, back pain, joint pain). The control group (30 patients) suffered from pain but had no stroke in anamnesis. Relationships between hemodynamic parameters and quantitative characteristics of chronic pain (visual analogue scale - VAS) were studied with help of linear Pearson correlation in different stroke periods and between the patients of Main and Control group.

RESULTS

Results: Strong correlations were found between decreasing in a.vertebralis blood flow and intensity of post-stroke pain. Strong correlations were found between intensivity of joint pain and a.vertebralis hemodynamic parameters in the patients in residual period up to 10 years. In the residual period over 10 years, in addition to the connections with hemodynamics in the VB, there was a correlation with the linear rapidly existing parameters of a.cerebri media, a.carotis communis.

CONCLUSION

Conclusions: Studying of hemodynamic parameters in patients with post-stroke pain syndromes can serve as a basis for a deeper understanding of pain mechanisms and the development of effective preventive and curative measures.

Palliative care approaches to acute stroke in the hospital setting

Stroke is a prevalent neurologic condition that portends a high risk of morbidity and mortality such that patients impacted by stroke and their caregivers can benefit from palliative care at the time of diagnosis and throughout the disease trajectory. Clinicians who care for stroke patients should be adept at establishing rapport with patients and caregivers, delivering serious news, responding to emotions, discussing prognosis, and establishing goals of care efficiently in an acute stroke setting. Aggressive stroke care can be integrated with a palliative approach to care that involves aligning the available treatment options with a patient's values and goals of care. Reassessing the goals throughout the hospitalization provides an opportunity for continued shared decision-making about the intensity of poststroke interventions. The palliative needs for stroke patients may increase over time depending on the severity of disease, poststroke complications, stroke-related symptoms, and treatment intensity preferences. If the decision is made to transition the focus of care to comfort, the support of an interdisciplinary palliative care or hospice team can be beneficial to the patient, family members, and surrogate decision makers.

"My Hand Is Different": Altered Body Perception in Stroke Survivors with Chronic Pain

BACKGROUND

Chronic pain and body perception disturbance are common following stroke. It is possible that an interaction exists between pain and body perception disturbance, and that a change in one may influence the other. We therefore investigated the presence of body perception disturbance in individuals with stroke, aiming to determine if a perceived change in hand size contralateral to the stroke lesion is more common in those with chronic pain than in those without.

METHODS

Stroke survivors (N = 523) completed an online survey that included: stroke details, pain features, and any difference in perceived hand size post-stroke.

RESULTS

Individuals with stroke who experienced chronic pain were almost three times as likely as those without chronic pain to perceive their hand as now being a different size (OR = 2.895; 95%CI 1.844, 4.547). Further, those with chronic pain whose pain included the hand were almost twice as likely to perceive altered hand size than those whose pain did not include the hand (OR = 1.862; 95%CI 1.170, 2.962). This was not influenced by hemisphere of lesion (p = 0.190).

CONCLUSIONS

The results point to a new characteristic of chronic pain in stroke, raising the possibility of body perception disturbance being a rehabilitation target to improve function and pain-related outcomes for stroke survivors.

Effectiveness of Botulinum Toxin on Pain in Stroke Patients Suffering from Upper Limb Spastic Dystonia

This observational study aimed at investigating pain in stroke patients with upper limb spastic dystonia. Forty-one consecutive patients were enrolled. A 0–10 numeric rating scale was used to evaluate pain at rest and during muscle tone assessment. Patients were asked to indicate the most painful joint at passive mobilization (shoulder, elbow, wrist-fingers). The DN4 questionnaire was administered to disclose neuropathic pain. All patients were assessed just before and 1 month after incobotulinumtoxin-A treatment. Pain was present in 22 patients, worsened or triggered by passive muscle stretching. DN4 scored < 4 in 20 patients. The most painful joints were wrist–fingers in 12 patients, elbow in 5 patients and shoulder in the remaining 5 patients. Both elbow and wrist–fingers pain correlated with muscle tone. BoNT-A treatment reduced pain in all the joints, including the shoulder. We discussed that nociceptive pain is present in a vast proportion of patients with upper limb spastic dystonia. BoNT-A treatment reduced both spastic dystonia and pain in all the joints but the shoulder, where the effect on pain could be mediated by the reduction of pathological postures involving the other joints.

Superior antioxidant and anti-ischemic neuroprotective effects of cerebrolysin in heat stroke following intoxication of engineered metal Ag and Cu nanoparticles: A comparative biochemical and physiological study with other stroke therapies

Military personnel are often exposed to high environmental heat associated with industrial or ambient abundance of nanoparticles (NPs) affecting brain function. We have shown that engineered metal NPs Ag and Cu exacerbate hyperthermia induced brain pathology. Thus, exploration of novel drug therapy is needed for effective neuroprotection in heat stroke intoxicated with NPs. In this investigation neuroprotective effects of cerebrolysin, a balanced composition of several neurotrophic factors and active peptides fragments exhibiting powerful antioxidant and anti-ischemic effects was examined in heat stroke after NPs intoxication. In addition, its efficacy is compared to currently used drugs in post-stroke therapies in clinics. Thus, levertiracetam, pregabalin, topiramat and valproate were compared in standard doses with cerebrolysin in heat stroke intoxicated with Cu or Ag NPs (50-60nm, 50mg/kg, i.p./day for 7 days). Rats were subjected to 4h heat stress (HS) in a biological oxygen demand incubator at 38°C (Relative Humidity 45-47%; Wind velocity 22.4-25.6cm/s) that resulted in profound increase in oxidants Luminol, Lucigenin, Malondialdehyde and Myeloperoxidase, and a marked decrease in antioxidant Glutathione. At this time severe reductions in the cerebral blood flow (CBF) was seen together with increased blood-brain barrier (BBB) breakdown and brain edema formation. These pathophysiological responses were exacerbated in NPs treated heat-stressed animals. Pretreatment with cerebrolysin (2.5mL/kg, i.v.) once daily for 3 days significantly attenuated the oxidative stress, BBB breakdown and brain edema and improved CBF in the heat stressed group. The other drugs were least effective on brain pathology following heat stroke. However, in NPs treated heat stressed animals 5mL/kg conventional cerebrolysin and 2.5mL/kg nanowired cerebrolysin is needed to attenuate oxidative stress, BBB breakdown, brain edema and to improve CBF. Interestingly, the other drugs even in higher doses used are unable to alter brain pathologies in NPs and heat stress. These observations are the first to demonstrate that cerebrolysin is the most superior antioxidant and anti-ischemic drug in NPs exposed heat stroke, not reported earlier.

The Effects of Gender, Functional Condition, and ADL on Pressure Pain Threshold in Stroke Patients

Background

Somatosensory impairments and pain are common symptoms following stroke. However, the condition of perception and pain threshold for pressure stimuli and the factors that can influence this in individuals with stroke are still unclear. This study aimed to investigate the gender differences in pressure pain threshold (PPT) and positive somatosensory signs for pressure stimuli, and explore the effects of joint pain, motor function, and activities of daily living (ADL) on pain threshold in post-stroke patients.

Design

A cross-sectional study.

Methods

A total of 60 participants with stroke were recruited, and their pain condition, motor functions, and ADL were evaluated by the Fugl-Meyer assessment of joint pain scale, motor function scale, and Barthel index, respectively. PPTs in eight tested points at the affected and unaffected sides were assessed.

Results

Significant differences in PPTs were found between male and female patients in all measured muscles (p < 0.05). Positive somatosensory signs for pressure stimuli, including hypoalgesia and hyperalgesia, were frequently found at the affected side, particularly in the extremity muscles, but such signs were not significantly influenced by gender (p > 0.05). More equal PPTs between both sides and relatively lower PPTs at the affected side in the trunk and medial gastrocnemius muscles (p < 0.05) were observed in patients with less pain, better motor functions, and ADL.

Conclusion

Gender differences widely exist in post-stroke survivors either at the affected or unaffected side, which are multifactorial. Sensory loss and central and/or peripheral sensitization, such as hypoalgesia and hyperalgesia for pressure stimuli, caused by a brain lesion are common signs in male and female stroke patients. Moreover, patients who are in a better condition show a more symmetrical pain sensitivity between both sides in the trunk and in female lower extremities, indicating the bidirectional improvement of somatosensory abnormalities caused by a possible neural plasticity.

Care of the Patient With Acute Ischemic Stroke (Posthyperacute and Prehospital Discharge): Update to 2009 Comprehensive Nursing Care Scientific Statement: A Scientific Statement From the American Heart Association

In 2009, the American Heart Association/American Stroke Association published a comprehensive scientific statement detailing the nursing care of the patient with an acute ischemic stroke through all phases of hospitalization. The purpose of this statement is to provide an update to the 2009 document by summarizing and incorporating current best practice evidence relevant to the provision of nursing and interprofessional care to patients with ischemic stroke and their families during the acute (posthyperacute phase) inpatient admission phase of recovery. Many of the nursing care elements are informed by nurse-led research to embed best practices in the provision and standard of care for patients with stroke. The writing group comprised members of the Stroke Nursing Committee of the Council on Cardiovascular and Stroke Nursing and the Stroke Council. A literature review was undertaken to examine the best practices in the care of the patient with acute ischemic stroke. The drafts were circulated and reviewed by all committee members. This statement provides a summary of best practices based on available evidence to guide nurses caring for adult patients with acute ischemic stroke in the hospital posthyperacute/intensive care unit. In many instances, however, knowledge gaps exist, demonstrating the need for continued nurse-led research on care of the patient with acute ischemic stroke.

Dry needling for the management of spasticity, pain, and range of movement in adults after stroke: A systematic review

OBJECTIVE

To summarise the available evidence about the effectiveness of deep dry needling (DN) on spasticity, pain-related outcomes, and range-of-movement (ROM) in adults after stroke.

DESIGN

A computer search of Web of Science, Scopus, Medline, Cochrane Library, Cinahl, and Physiotherapy Evidence Database (PEDro) was conducted. A hand search of the reference lists of the selected studies and other relevant publications was also undertaken. Studies were assessed by two independent reviewers and included if they complied with the following criteria: (1) participants were adults after a stroke, (2) use of DN alone or within a multimodal approach, compared to no intervention or other treatments; (3) assessment of spasticity, pain, or joint ROM as a primary or secondary outcome. We included randomised controlled trials (RCTs), case series, and case reports. Data were extracted using a standardised protocol. The methodological quality of the studies was assessed with the Checklist for Measuring quality.

RESULTS

A total of sixteen studies, 7 of which were RCTs, were selected. All studies generally reported an improvement of spasticity level, pain intensity, and ROM after the use of DN, alone or combined with other interventions, in stroke survivors.

CONCLUSION

The management of adults after stroke with DN may impact positively on spasticity, pain, and ROM. However, there was significant heterogeneity across trials in terms of sample size, control groups, treated muscles, and outcome measures, and a meta-analysis was not feasible. Further research should include proper blinding, sham placebo DN as control intervention, and investigate long-term effects.