Non-invasive brain microcurrent stimulation therapy of long-COVID-19 reduces vascular dysregulation and improves visual and cognitive impairment

Background: An effective treatment is needed for long-COVID patients which suffer from symptoms of vision and/or cognition impairment such as impaired attention, memory, language comprehension, or fatigue. Objective: Because COVID-19infection causes reduced blood flow which may cause neuronal inactivation, we explored if neuromodulation with non-invasive brain stimulation with microcurrent (NIBS), known to enhance blood flow and neuronal synchronization, can reduce these symptoms. Methods: Two female long-COVID patients were treated for 10–13 days with alternating current stimulation of the eyes and brain. While one patient (age 40) was infected with the SARS CoV-2 virus, the other (age 72) developed symptoms following AstraZeneca vaccination. Before and after therapy, cognition was assessed subjectively by interview and visual field using perimetry. One patient was also tested with a cognitive test battery and with a retinal dynamic vascular analyser (DVA), a surrogate marker of vascular dysregulation in the brain. Results: In both patients NIBS markedly improved cognition and partially reversed visual field loss within 3–4 days. Cognitive tests in one patient confirmed recovery of up to 40–60% in cognitive subfunctions with perimetry results showing stable and visual field recovery even during follow-up. DVA showed that NIBS reduced vascular dysregulation by normalizing vessel dynamics (dilation/constriction), with particularly noticeable changes in the peripheral veins and arteries. Conclusions: NIBS was effective in improving visual and cognitive deficits in two confirmed SARS-COV-2 patients. Because recovery of function was associated with restoration of vascular autoregulation, we propose that (i) hypometabolic, “silent” neurons are the likely biological cause of long-COVID associated visual and cognitive deficits, and (ii) reoxygenation of these “silent” neurons provides the basis of neurological recovery. Controlled trials are now needed to confirm these observations.

It Cuts Both Ways: An Annelid Model System for the Study of Regeneration in the Laboratory and in the Classroom

The mechanisms supporting regeneration and successful recovery of function have fascinated scientists and the general public for quite some time, with the earliest description of regeneration occurring in the 8th century BC through the Greek mythological story of Prometheus. While most animals demonstrate the capacity for wound-healing, the ability to initiate a developmental process that leads to a partial or complete replacement of a lost structure varies widely among animal taxa. Variation also occurs within single species based on the nature and location of the wound and the developmental stage or age of the individual. Comparative studies of cellular and molecular changes that occur both during, and following, wound healing may point to conserved genomic pathways among animals of different regenerative capacity. Such insights could revolutionize studies within the field of regenerative medicine. In this review, we focus on several closely related species of Lumbriculus (Clitellata: Lumbriculidae), as we present a case for revisiting the use of an annelid model system for the study of regeneration. We hope that this review will provide a primer to Lumbriculus biology not only for regeneration researchers but also for STEM teachers and their students.

Repositioning maneuvers in benign paroxysmal positional vertigo: how do we improve outcomes?

Benign paroxysmal positional vertigo (BPPV) is the most common peripheral vestibular disorder. A series of meetings with clinicians treating BPPV were conducted to seek their views on improving outcomes in patients with BPPV. BPPV is primarily treated by Otolith repositioning maneuvers (ORM) to help to move the otoconia out of the canal and lead it back to the vestibule. Although repositioning maneuvers are effective in BPPV management, some patients experience residual dizziness, postural instability, recurrences, and psycho-emotional consequences after about 1 month after repositioning. An important and useful non-pharmacological intervention for patients with balance disturbances is Vestibular rehabilitation (VR), which includes vestibular adaptation, habituation and substitution, and patient education. Repositioning devices and mastoid vibration could help a subgroup of patients with BPPV who do not respond to conventional management. Betahistine dihydrochloride accelerates the recovery of function of vestibular system by improving blood flow in the inner ear, and normalization of the function of motion sensitive hair cells is faster. Betahistine-treated patients may have faster recovery, lesser recurrence, and longer relief of symptoms. The use of betahistine in combination with maneuvers can help prevent the development of residual dizziness.

The Emergence of Stereotyped Kinematic Synergies when Mice Reach to Grasp Following Stroke

Reaching tasks are commonly used in preclinical and clinical studies to assess the acquisition of fine motor skills and recovery of function following stroke. These tasks are often used to assess functional deficits in the absence of quantifying the quality of movement which requires kinematic analysis. To meet this need, this study uses a kinematic analysis in mice performing the Montoya staircase task at 5 and 14 days following a cortical photothrombosis-induced stroke. Following stroke, the mice had reaching impairments associated with sustained deficits including longer, unsmooth, and less individuated paw trajectories. Two weeks after stroke we also detected the emergence of abnormal elbow and shoulder angles, flexion/extensions, and stereotyped kinematic synergies. These data suggest that proximal and distal segments acting in concert is paramount during post-stroke reaching and encourage further analysis of synergies within the translational pipeline of preclinical to clinical studies.

A Behavioural Analysis of Serotonergic Functional Status Following MDMA Exposure

<p>Rationale +/- 3,4-Methylenedioxymethamphetamine (MDMA) produces effects on a number of neurochemical systems. Many studies have shown that repeated MDMA administration produces deficits in central serotonergic neurotransmission, which have been suggested to underlie some of the behavioural changes associated with use. Objectives The present studies sought to evaluate the functional statuses of the serotonin transporter (SERT) and the serotonin2c (5-HT2c) and serotonin2a (5-HT2a) receptors following treatment with MDMA to determine whether behavioural deficits could be attributed to alterations in these proteins. Methods Rats received a pretreatment regimen of MDMA (4 x 10mg/kg MDMA injections administered at 2h intervals) or the saline vehicle and, 2 weeks later, [3H] paroxetine binding was undertaken to assess densities of SERT. In other groups, dose-effect curves for MDMA-produced hyperactivity were determined. Additional groups were tested following a 12-week withdrawal period from MDMA in order to assess whether there was recovery of function. The functional status of the SERT was further examined by determining the effect of MDMA pretreatment on the reduction in MDMA-produced hyperactivity (0.0 - 10.0mg/kg) produced by the selective serotonin reuptake inhibitor, clomipramine (0.0 - 5.0mg/kg). The ability for the 5-HT2c receptor agonist, m-CPP (0.0 - 2.5mg/kg) to produce hypolocomotion or increased emergence latency or for the 5-HT2a receptor agonist, DOI (0.0 - 2.0mg/kg) to produce wetdog shakes (WDS) were examined in MDMA pretreated rats. The ability for the 5-HT2c receptors to modulate MDMA-produced hyperactivity was assessed by examining the effect of MDMA pretreatment on the potentiation of MDMA-produced hyperactivity produced by the selective antagonist, RS102221 (0.0 - 1.0mg/kg). Conversely, the modulatory abilities of the 5-HT2a receptors were assessed by examining the effect of MDMA pretreatment on the attenuation of MDMA-produced hyperactivity produced by the antagonist, ritanserin (0.0 - 10.0mg/kg). Results MDMA pretreatment produced widespread reductions in SERT binding densities 2 weeks following administration. Prior exposure to MDMA rendered rats tolerant to MDMA-produced hyperactivity when tested 2, but not 12, weeks following MDMA administration. Two weeks following MDMA pretreatment rats were also less responsive to the clomipramine-produced attenuation of MDMA-produced hyperactivity. MDMA pretreatment failed to alter M-CPP -produced hypolocomotion or increased emergence latency, but decreased the ability for DOI to induce WDS. Further, MDMA pretreated rats exhibited tolerance to RS102221 as shown by a rightward shift in the dose effect curve and complete tolerance to ritanserin. Conclusions Following MDMA pretreatment, the decreased SERT binding densities and inability of clomipramine to attenuate MDMA-produced effects might explain tolerance to the locomotor activating effects produced by MDMA. Functional recovery also occurred with extended abstinence from the drug, suggesting that MDMA produced transient serotonergic alterations. The results support the idea that the 5-HT2a and 5-HT2c receptors that modulate MDMA-produced hyperactivity are functionally distinct from the receptors that mediate m-CPP- and DOI-induced behavioural responses, as m-CPP-produced behaviours were resilient, yet RS102221-induced effects were reduced, by MDMA pretreatment. RS102221 is highly selective in comparison to ritanserin, yet there was only one dose that produced significant potentiation of MDMA-produced hyperactivity, whereas there were several effective ritanserin doses. This suggests that the 5-HT2a receptors had a greater role in modulating MDMA-produced hyperactivity. Additionally, 5-HT2a receptors might be more susceptible to MDMA-induced desensitisation than 5-HT2c receptors, as MDMA pretreated rats exhibited some tolerance to the potentiating effects of RS102221 but were unresponsive to any ritanserin dose. In conclusion, MDMA-induced locomotor tolerance was attributable to decreased SERT densities and function as well as desensitisation of 5-HT2a receptors that facilitate hyperactivity.</p>

A Behavioural Analysis of Serotonergic Functional Status Following MDMA Exposure

<p>Rationale +/- 3,4-Methylenedioxymethamphetamine (MDMA) produces effects on a number of neurochemical systems. Many studies have shown that repeated MDMA administration produces deficits in central serotonergic neurotransmission, which have been suggested to underlie some of the behavioural changes associated with use. Objectives The present studies sought to evaluate the functional statuses of the serotonin transporter (SERT) and the serotonin2c (5-HT2c) and serotonin2a (5-HT2a) receptors following treatment with MDMA to determine whether behavioural deficits could be attributed to alterations in these proteins. Methods Rats received a pretreatment regimen of MDMA (4 x 10mg/kg MDMA injections administered at 2h intervals) or the saline vehicle and, 2 weeks later, [3H] paroxetine binding was undertaken to assess densities of SERT. In other groups, dose-effect curves for MDMA-produced hyperactivity were determined. Additional groups were tested following a 12-week withdrawal period from MDMA in order to assess whether there was recovery of function. The functional status of the SERT was further examined by determining the effect of MDMA pretreatment on the reduction in MDMA-produced hyperactivity (0.0 - 10.0mg/kg) produced by the selective serotonin reuptake inhibitor, clomipramine (0.0 - 5.0mg/kg). The ability for the 5-HT2c receptor agonist, m-CPP (0.0 - 2.5mg/kg) to produce hypolocomotion or increased emergence latency or for the 5-HT2a receptor agonist, DOI (0.0 - 2.0mg/kg) to produce wetdog shakes (WDS) were examined in MDMA pretreated rats. The ability for the 5-HT2c receptors to modulate MDMA-produced hyperactivity was assessed by examining the effect of MDMA pretreatment on the potentiation of MDMA-produced hyperactivity produced by the selective antagonist, RS102221 (0.0 - 1.0mg/kg). Conversely, the modulatory abilities of the 5-HT2a receptors were assessed by examining the effect of MDMA pretreatment on the attenuation of MDMA-produced hyperactivity produced by the antagonist, ritanserin (0.0 - 10.0mg/kg). Results MDMA pretreatment produced widespread reductions in SERT binding densities 2 weeks following administration. Prior exposure to MDMA rendered rats tolerant to MDMA-produced hyperactivity when tested 2, but not 12, weeks following MDMA administration. Two weeks following MDMA pretreatment rats were also less responsive to the clomipramine-produced attenuation of MDMA-produced hyperactivity. MDMA pretreatment failed to alter M-CPP -produced hypolocomotion or increased emergence latency, but decreased the ability for DOI to induce WDS. Further, MDMA pretreated rats exhibited tolerance to RS102221 as shown by a rightward shift in the dose effect curve and complete tolerance to ritanserin. Conclusions Following MDMA pretreatment, the decreased SERT binding densities and inability of clomipramine to attenuate MDMA-produced effects might explain tolerance to the locomotor activating effects produced by MDMA. Functional recovery also occurred with extended abstinence from the drug, suggesting that MDMA produced transient serotonergic alterations. The results support the idea that the 5-HT2a and 5-HT2c receptors that modulate MDMA-produced hyperactivity are functionally distinct from the receptors that mediate m-CPP- and DOI-induced behavioural responses, as m-CPP-produced behaviours were resilient, yet RS102221-induced effects were reduced, by MDMA pretreatment. RS102221 is highly selective in comparison to ritanserin, yet there was only one dose that produced significant potentiation of MDMA-produced hyperactivity, whereas there were several effective ritanserin doses. This suggests that the 5-HT2a receptors had a greater role in modulating MDMA-produced hyperactivity. Additionally, 5-HT2a receptors might be more susceptible to MDMA-induced desensitisation than 5-HT2c receptors, as MDMA pretreated rats exhibited some tolerance to the potentiating effects of RS102221 but were unresponsive to any ritanserin dose. In conclusion, MDMA-induced locomotor tolerance was attributable to decreased SERT densities and function as well as desensitisation of 5-HT2a receptors that facilitate hyperactivity.</p>

Ultrastructural Adaptation of the Cardiomyocyte to Chronic Mitral Regurgitation

Introduction: Mitral regurgitation (MR) imposes volume overload on the left ventricle (LV) and elevates wall stress, triggering its adverse remodeling. Pronounced LV dilation, minimal wall thinning, and a gradual decline in cardiac ejection fraction (EF) are observed. The structural changes in the myocardium that define these gross, organ level remodeling are not known. Cardiomyocyte elongation and slippage have both been hypothesized, but neither are confirmed, nor are the changes to the cardiomyocyte structure known. Using a rodent model of MR, we used immunohistochemistry and transmission electron microscopy (TEM) to describe the ultrastructural remodeling of the cardiomyocyte.Methods: Twenty-four male Sprague-Dawley rats (350–400 g) were assigned to two groups: group (1) rats induced with severe MR (n = 18) and group (2) control rats that were healthy and age and weight matched (n = 6). MR was induced in the beating heart using a 23-G ultrasound-guided, transapical needle to perforate the anterior mitral leaflet, and the rats were followed to 2, 10, and 20 weeks (n = 6/time-point). Echocardiography was performed to quantify MR severity and to measure LV volume and function at each time-point. Explanted myocardial tissue were examined with TEM and immunohistochemistry to investigate the ultrastructural changes.Results: MR induced rapid and significant increase in end-diastolic volume (EDV), with a 50% increase by 2 weeks, compared with control. Rise in end-systolic volume (ESV) was more gradual; however, by 20 weeks, both EDV and ESV in MR rats were increased by 126% compared with control. A significant decline in EF was measured at 10 weeks of MR. At the ultrastructural level, as early as 2 weeks after MR, cardiomyocyte elongation and increase in cross-sectional area were observed. TEM depicted sarcomere shortening, with loss of Z-line and I-band. Desmin, a cytoskeletal protein that is uniformly distributed along the length of the cardiomyocyte, was disorganized and localized to the intercalated disc, in the rats induced with MR and not in the controls. In the rats with MR, the linear registry of the mitochondrial arrangement along the sarcomeres was lost, with mitochondrial fragmentation, aggregation around the nucleus, and irregularities in the cristae.Discussion: In the setting of chronic mitral regurgitation, LV dilatation occured by cardiomyocyte elongation, which manifests at the subcellular level as distinct ultrastructural alterations of the sarcomere, cytoskeleton, and mitochondria. Since the cytoskeleton not only provides tensegrity but has functional consequences on myocyte function, further investigation into the impact of cytoskeletal remodeling on progressive heart failure or recovery of function upon correcting the valve lesion are needed.

Identification of the Adult Hematopoietic Liver as the Primary Reservoir for the Recruitment of Pro-regenerative Macrophages Required for Salamander Limb Regeneration

The lack of scar-free healing and regeneration in many adult human tissues imposes severe limitations on the recovery of function after injury. In stark contrast, salamanders can functionally repair a range of clinically relevant tissues throughout adult life. The impressive ability to regenerate whole limbs after amputation, or regenerate following cardiac injury, is critically dependent on the recruitment of (myeloid) macrophage white blood cells to the site of injury. Amputation in the absence of macrophages results in regeneration failure and scar tissue induction. Identifying the exact hematopoietic source or reservoir of myeloid cells supporting regeneration is a necessary step in characterizing differences in macrophage phenotypes regulating scarring or regeneration across species. Mammalian wounds are dominated by splenic-derived monocytes that originate in the bone marrow and differentiate into macrophages within the wound. Unlike mammals, adult axolotls do not have functional bone marrow but instead utilize liver and spleen tissues as major sites for adult hematopoiesis. To interrogate leukocyte identity, tissue origins, and modes of recruitment, we established several transgenic axolotl hematopoietic tissue transplant models and flow cytometry protocols to study cell migration and identify the source of pro-regenerative macrophages. We identified that although bidirectional trafficking of leukocytes can occur between spleen and liver tissues, the liver is the major source of leukocytes recruited to regenerating limbs. Recruitment of leukocytes and limb regeneration occurs in the absence of the spleen, thus confirming the dependence of liver-derived myeloid cells in regeneration and that splenic maturation is dispensable for the education of pro-regenerative macrophages. This work provides an important foundation for understanding the hematopoietic origins and education of myeloid cells recruited to, and essential for, adult tissue regeneration.

Brachial Plexus Injury Surgical Service in Time of Coronavirus Disease 2019 Pandemic Experience from a Single Tertiary Orthopaedic Hospital in Indonesia

BACKGROUND: Brachial plexus injury (BPI) is one of the most devastating nerve injuries to the extremities. BPI in adults is an increasingly common clinical problem due to road traffic accident. Injury patterns, the timing of surgery, priority on the recovery of function, and patient’s understanding about the expectations of the prognosis are things that are important to consider before deciding on surgical management. The coronavirus pandemic coronavirus disease 2019 (COVID-19) has significantly affected all sectors, one of which is a surgical practice both in terms of medical personnel and equipment, also patient perceptions of hospital services. AIM: This study will analyze epidemiological data on BPI patients who underwent surgery during the COVID-19 pandemic. METHODS: A retrospective descriptive study of BPI profile in Prof. Soeharso Orthopedic Hospital before (2019) and during (2020) the COVID-19 pandemic. Demographic data, the total number of surgery, type of surgical procedure, and patient origin were collected. We compared to the same period in 2019 before pandemic started. RESULTS: In the data obtained from patients treated or undergoing BPI surgery before pandemic (March 1, 2019 to December 31, 2019) and during the pandemic (March 1, 2020 to December 31, 2020), Indonesia first confirms case was on March 2, 2020, until today. There were 51 and 43 cases, respectively. Panplexal type before the pandemic there were 27 patients (52%), and during the pandemic were 20 patients (46%), the upper type before: during the pandemic was 24 (48%): 23 (54%), and lower type 0 cases. Primary reconstruction before: during the pandemic was 26 (55%): 27 (62%) case, and secondary reconstruction before: during the pandemic was 25 (49%): 16 (38%) case, respectively. CONCLUSION: COVID-19 pandemic has no significant effect in the term of the number of BPI surgery performed. Better outcome in BPI surgery is influenced by the timing of the operation, therefore primary reconstruction remains the main choice for BPI patients with safety concern or health protocols. Pre-operative screening applied in our hospital includes laboratory examination, chest radiograph, and polymerase chain reaction swab test. Surgical personnel using personal protective equipment such as protective suit, face shield, google, shoes and medical mask during the COVID-19 pandemic. Patients with significant axon loss and limited clinical recovery are considered “urgent”, as surgery should be performed within 6 months or sooner (depending upon the distance to recipient’s muscle) to avoid irreversible muscle atrophy and degradation of motor endplates.

Nerve grafts and transfers

Following Cruickshank’s (1795) ingenious (and at first disbelieved) demonstration of the regenerative capacity of mammalian nerves, the eighteenth and nineteenth centuries saw a pan-European enthusiasm to redress the nihilism surrounding nerve injury. The first recorded experimental nerve grafts were performed by Philipeaux and Vulpian who attempted both nerve autografting as well as allografting in dogs. At that time, and for many years, allografts were thought to behave similarly to autografts, a belief that persisted well into the twentieth century in some clinics and laboratories. These early attempts at nerve grafting yielded poor results and most surgeons aimed for primary nerve repair despite nerve gaps. Other techniques to allow direct repair involved alteration of position, transposition of the nerve, and even sometimes bone shortening. Although primary repair was frequently possible, after these measures the repair was under tension and mechanical failure was common. Spurling (1945), Whitcomb (1946), and Woodall (1956) showed failure rates of 4%, 7.5%, and 22.4% respectively. Some recovery of function following nerve grafting was documented by Sanders (1942), Seddon (1954), and Brooks (1955). Millesi subsequently published his results for nerve grafting for injuries to the upper limb in 1984. These papers demonstrated more significant recovery of function and highlighted the detriment of delay in treatment to final outcome. Microsurgical advances were central to Millesi’s results, and he emphasized atraumatic dissection and the deleterious effect of tension at the repair site resulting in fibrosis preventing axonal regrowth. Nerve autograft is now the standard for orthotopic nerve reconstruction when primary repair cannot be achieved.