Genetic control of neuronal activity enhances axonal growth only on permissive substrates.

BACKGROUND: Neural tissue has limited regenerative ability. To cope with that, in recent years a diverse set of novel tools has been used to tailor neurostimulation therapies and promote functional regeneration after axonal injuries. METHOD: In this report, we explore cell-specific methods to modulate neuronal activity, including opto- and chemogenetics to assess the effect of specific neuronal stimulation in the promotion of axonal regeneration after injury. RESULTS: Opto- and chemogenetic stimulations of neuronal activity elicited increased in vitro neurite outgrowth in both sensory and cortical neurons, as well as in vivo regeneration in the sciatic nerve, but not after spinal cord injury. Mechanistically, inhibitory substrates such as chondroitin sulfate proteoglycans block the activity induced increase in axonal growth. CONCLUSIONS: We found that genetic modulations of neuronal activity on both dorsal root ganglia and corticospinal motor neurons increase their axonal growth capacity but only on permissive environments.

Effectiveness of an App for tobacco cessation in pregnant smokers (TOBBGEST): study protocol.

BACKGROUND: Tobacco consumption during pregnancy is one of the most modifiable causes of morbidity and mortality for both pregnant smokers and their foetus. Even though pregnant smokers are conscious about the negative effects of tobacco consumption, they also had barriers for smoking cessation and most of them continue smoking, being a major public health problem. The aim of this study is to determine the effectiveness of an application (App) for mobile devices, designed with a gamification strategy, in order to help pregnant smokers to quit smoking during pregnancy and in the long term. METHODS: This study is a multicentre randomized community intervention trial. It will recruit pregnant smokers (200 participants/group), aged more than 18 years, with sporadically or daily smoking habit in the last 30 days and who follow-up their pregnancy in the Sexual and Reproductive Health Care Services of the Camp de Tarragona and Central Catalonia Primary Care Departments. All the participants will have the usual clinical practice intervention for smoking cessation, whereas the intervention group will also have access to the App. The outcome measure will be prolonged abstinence at 12 months after the intervention, as confirmed by expired-carbon monoxide and urinary cotinine tests. Results will be analysed based on intention to treat. Prolonged abstinence rates will be compared, and the determining factors will be evaluated using multivariate statistical analysis. DISCUSSION: The results of this study will offer evidence about the effectiveness of an intervention using a mobile App in smoking cessation for pregnant smokers, to decrease comorbidity associated with long-term smoking. If this technology is proven effective, it could be readily incorporated into primary care intervention for all pregnant smokers. TRIAL REGISTRATION: Clinicaltrials.gov ID NCT05222958 . Trial registered 3 February 2022.

Monoacylglycerol lipase blockade impairs fine motor coordination and triggers cerebellar neuroinflammation through cyclooxygenase-2.

Monoacylglycerol lipase (MAGL) is the main enzyme implicated in the degradation of the most abundant endocannabinoid in the brain, 2-arachidonoylglycerol (2-AG), producing arachidonic acid (AA) and glycerol. MAGL pharmacological inhibition with JZL184 or genetic deletion results in an exacerbated 2-AG signaling and reduced synthesis of prostaglandins (PGs), due to the reduced AA precursor levels. We found that acute JZL184 administration, previously described to exert anti-inflammatory effects, and MAGL knockout (KO) mice display cerebellar, but not hippocampal, microglial reactivity, accompanied with increased expression of the mRNA levels of neuroinflammatory markers, such as cyclooxygenase-2 (COX-2). Notably, this neuroinflammatory phenotype correlated with relevant motor coordination impairment in the beam-walking and the footprint tests. Treatment with the COX-2 inhibitor NS398 during 5 days prevented the deficits in cerebellar function and the cerebellar microglia reactivity in MAGL KO, without affecting hippocampal reactivity. Altogether, this study reveals the brain region-specific response to MAGL inhibition, with an important role of COX-2 in the cerebellar deficits associated, which should be taken into account for the use of MAGL inhibitors as anti-inflammatory drugs.

Pharmacogenetic modulation of STEP improves motor and cognitive function in a mouse model of Huntington's disease.

Huntington's disease (HD) is a hereditary neurodegenerative disorder caused by an expansion of a CAG repeat in the huntingtin (htt) gene, which results in an aberrant form of the protein (mhtt). This leads to motor and cognitive deficits associated with corticostriatal and hippocampal alterations. The levels of STriatal-Enriched protein tyrosine Phosphatase (STEP), a neural-specific tyrosine phosphatase that opposes the development of synaptic strengthening, are decreased in the striatum of HD patients and also in R6/1 mice, thereby contributing to the resistance to excitotoxicity described in this HD mouse model. Here, we aimed to analyze whether STEP inactivation plays a role in the pathophysiology of HD by investigating its effect on motor and cognitive impairment in the R6/1 mouse model of HD. We found that genetic deletion of STEP delayed the onset of motor dysfunction and prevented the appearance of cognitive deficits in R6/1 mice. This phenotype was accompanied by an increase in pERK1/2 levels, a delay in the decrease of striatal DARPP-32 levels and a reduction in the size of mhtt aggregates, both in the striatum and CA1 hippocampal region. We also found that acute pharmacological inhibition of STEP with TC-2153 improved cognitive function in R6/1 mice. In conclusion, our results show that deletion of STEP has a beneficial effect on motor coordination and cognition in a mouse model of HD suggesting that STEP inhibition could be a good therapeutic strategy in HD patients.

Online platform for cardiopulmonary resuscitation and automated external defibrillator training in a rural area: a community clinical trial protocol.

INTRODUCTION: Sudden death resulting from cardiorespiratory arrest carries a high mortality rate and frequently occurs out of hospital. Immediate initiation of cardiopulmonary resuscitation (CPR) by witnesses, combined with automated external defibrillator (AED) use, has proven to double survival rates. Recognising the challenges of timely emergency services in rural areas, the implementation of basic CPR training programmes can improve survival outcomes. This study aims to evaluate the effectiveness of online CPR-AED training among residents in a rural area of Tarragona, Spain. METHODS: Quasi-experimental design, comprising two phases. Phase 1 involves assessing the effectiveness of online CPR-AED training in terms of knowledge acquisition. Phase 2 focuses on evaluating participant proficiency in CPR-AED simulation manoeuvres at 1 and 6 months post training. The main variables include the score difference between pre-training and post-training test (phase 1) and the outcomes of the simulated test (pass/fail; phase 2). Continuous variables will be compared using Student's t-test or Mann-Whitney U test, depending on normality. Pearson's χ2 test will be applied for categorical variables. A multivariate analysis will be conducted to identify independent factors influencing the main variable. ETHICS AND DISSEMINATION: This study adheres to the tenets outlined in the Declaration of Helsinki and of Good Clinical Practice. It operated within the Smartwatch project, approved by the Clinical Research Ethics Committee of the Primary Care Research Institute IDIAP Jordi Gol i Gurina Foundation, code 23/081-P. Data confidentiality aligns with Spanish and European Commission laws for the protection of personal data. The study's findings will be published in peer-reviewed journals and presented at scientific meetings. TRIAL REGISTRATION NUMBER: NCT05747495.

Patient Safety Incidents in Primary Care: Comparing APEAS-2007 (Spanish Patient Safety Adverse Events Study in Primary Care) with Data from a Health Area in Catalonia (Spain) in 2019.

The initial APEAS study, conducted in June 2007, examined adverse events (AEs) in Spanish Primary Healthcare (PHC). Since then, significant changes have occurred in healthcare systems. To evaluate these changes, a study was conducted in the Camp de Tarragona PHC region (CTPHC) in June 2019. This cross-sectional study aimed to identify AEs in 20 PHC centres in Camp de Tarragona. Data collection used an online questionnaire adapted from APEAS-2007, and a comparative statistical analysis between APEAS-2007 and CTPHC-2019 was performed. The results revealed an increase in nursing notifications and a decrease in notifications from family doctors. Furthermore, fewer AEs were reported overall, particularly in medication-related incidents and healthcare-associated infections, with an increase noted in no-harm incidents. However, AEs related to worsened clinical outcomes, communication issues, care management, and administrative errors increased. Concerning severity, there was a decrease in severe AEs, coupled with an increase in moderate AEs. Despite family doctors perceiving a reduction in medication-related incidents, the overall preventability of AEs remained unchanged. In conclusion, the reporting patterns, nature, and causal factors of AEs in Spanish PHC have evolved over time. While there has been a decrease in medication-related incidents and severe AEs, challenges persist in communication, care management, and clinical outcomes. Although professionals reported reduced severity, the perception of preventability remains an area that requires attention.

Injury-induced activation of the endocannabinoid system promotes axon regeneration.

Regeneration after a peripheral nerve injury still remains a challenge, due to the limited regenerative potential of axons after injury. While the endocannabinoid system (ECS) has been widely studied for its neuroprotective and analgesic effects, its role in axonal regeneration and during the conditioning lesion remains unexplored. In this study, we observed that a peripheral nerve injury induces axonal regeneration through an increase in the endocannabinoid tone. We also enhanced the regenerative capacity of dorsal root ganglia (DRG) neurons through the inhibition of endocannabinoid degradative enzyme MAGL or a CB1R agonist. Our results suggest that the ECS, via CB1R and PI3K-pAkt pathway activation, plays an important role in promoting the intrinsic regenerative capacity of sensory neurons after injury.

Peripheral CB1 receptor blockade acts as a memory enhancer through a noradrenergic mechanism.

Peripheral inputs continuously shape brain function and can influence memory acquisition, but the underlying mechanisms have not been fully understood. Cannabinoid type-1 receptor (CB1R) is a well-recognized player in memory performance, and its systemic modulation significantly influences memory function. By assessing low arousal/non-emotional recognition memory in mice, we found a relevant role of peripheral CB1R in memory persistence. Indeed, the peripherally-restricted CB1R specific antagonist AM6545 showed significant mnemonic effects that were occluded in adrenalectomized mice, and after peripheral adrenergic blockade. AM6545 also transiently impaired contextual fear memory extinction. Vagus nerve chemogenetic inhibition reduced AM6545-induced mnemonic effect. Genetic CB1R deletion in dopamine ß-hydroxylase-expressing cells enhanced recognition memory persistence. These observations support a role of peripheral CB1R modulating adrenergic tone relevant for cognition. Furthermore, AM6545 acutely improved brain connectivity and enhanced extracellular hippocampal norepinephrine. In agreement, intra-hippocampal ß-adrenergic blockade prevented AM6545 mnemonic effects. Altogether, we disclose a novel CB1R-dependent peripheral mechanism with implications relevant for lengthening the duration of non-emotional memory.

Nociception-Dependent CCL21 Induces Dorsal Root Ganglia Axonal Growth via CCR7-ERK Activation.

While chemokines were originally described for their ability to induce cell migration, many studies show how these proteins also take part in many other cell functions, acting as adaptable messengers in the communication between a diversity of cell types. In the nervous system, chemokines participate both in physiological and pathological processes, and while their expression is often described on glial and immune cells, growing evidence describes the expression of chemokines and their receptors in neurons, highlighting their potential in auto- and paracrine signalling. In this study we analysed the role of nociception in the neuronal chemokinome, and in turn their role in axonal growth. We found that stimulating TRPV1+ nociceptors induces a transient increase in CCL21. Interestingly we also found that CCL21 enhances neurite growth of large diameter proprioceptors in vitro. Consistent with this, we show that proprioceptors express the CCL21 receptor CCR7, and a CCR7 neutralizing antibody dose-dependently attenuates CCL21-induced neurite outgrowth. Mechanistically, we found that CCL21 binds locally to its receptor CCR7 at the growth cone, activating the downstream MEK-ERK pathway, that in turn activates N-WASP, triggering actin filament ramification in the growth cone, resulting in increased axonal growth.

Type 2 Diabetes Mellitus and COVID-19: A Narrative Review.

Type-2 diabetes mellitus (T2DM) is a chronic metabolic disorder. The incidence and prevalence of patients with T2DM are increasing worldwide, even reaching epidemic values in most high- and middle-income countries. T2DM could be a risk factor of developing complications in other diseases. Indeed, some studies suggest a bidirectional interaction between T2DM and COVID-19. A growing body of evidence shows that COVID-19 prognosis in individuals with T2DM is worse compared with those without. Moreover, various studies have reported the emergence of newly diagnosed patients with T2DM after SARS-CoV-2 infection. The most common treatments for T2DM may influence SARS-CoV-2 and their implication in infection is briefly discussed in this review. A better understanding of the link between TD2M and COVID-19 could proactively identify risk factors and, as a result, develop strategies to improve the prognosis for these patients.

Use of the Vsoc-maze to Study Sociability and Preference for Social Novelty in Rodents.

Studying social behavior in mouse models empowers the understanding of the neurobiological mechanisms involved, which are affected in neuropsychiatric disorders, allowing the evaluation of therapeutic strategies. Behavioral methods available are time-consuming and reducing the length of behavioral sessions may render more manageable experiments and reduce animal stress. We validated a new reliable and sensitive method to study two features of social behavior (sociability and preference for social novelty) in two strains of male mice, the C57BL/6J inbreed strain and the CD1 (ICR) outbreed strain, using a modified version of the V-shaped maze (Vsoc-maze). The Vsoc-maze for sociability and preference for social novelty improves time performance by shortening the length of the sessions, and reduces variability compared to the classical approach performed in the three-chamber apparatus. Altogether, the Vsoc-maze allows evaluating the specific alterations of social behavior in mice in a time-efficient and reproducible manner.

Proteolytic Degradation of Hippocampal STEP61 in LTP and Learning.

Striatal-enriched protein tyrosine phosphatase (STEP) modulates key signaling molecules involved in synaptic plasticity and neuronal function. It is postulated that STEP opposes the development of long-term potentiation (LTP) and that it exerts a restraint on long-term memory (LTM). Here, we examined whether STEP61 levels are regulated during hippocampal LTP and after training in hippocampal-dependent tasks. We found that after inducing LTP by high frequency stimulation or theta-burst stimulation STEP61 levels were significantly reduced, with a concomitant increase of STEP33 levels, a product of calpain cleavage. Importantly, inhibition of STEP with TC-2153 improved LTP in hippocampal slices. Moreover, we observed that after training in the passive avoidance and the T-maze spontaneous alternation task, hippocampal STEP61 levels were significantly reduced, but STEP33 levels were unchanged. Yet, hippocampal BDNF content and TrkB levels were increased in trained mice, and it is known that BDNF promotes STEP degradation through the proteasome. Accordingly, hippocampal pTrkBTyr816, pPLCγTyr783, and protein ubiquitination levels were increased in T-SAT trained mice. Remarkably, injection of the TrkB antagonist ANA-12 (2 mg/Kg, but not 0.5 mg/Kg) elicited LTM deficits and promoted STEP61 accumulation in the hippocampus. Also, STEP knockout mice outperformed wild-type animals in an age- and test-dependent manner. Summarizing, STEP61 undergoes proteolytic degradation in conditions leading to synaptic strengthening and memory formation, thus highlighting its role as a molecular constrain, which is removed to enable the activation of pathways important for plasticity processes.

Combining Russian stimulation with isometric exercise improves strength, balance, and mobility in older people with falls syndrome.

One of the main causes of falls in older people is muscle strength loss associated with aging. Russian stimulation can improve muscle strength in healthy individuals, but the effect has never been tested in older individuals with falls syndrome. The aim of this study was to evaluate the usefulness of Russian stimulation plus isometric exercise to improve muscular strength, balance, and mobility in older people with falls syndrome. The recruited participants (older than 60 years, at least one fall in the past year) were evaluated by a physiatrist, who collected clinical data and performed baseline and final evaluations (muscle strength, Berg balance scale, Tinetti mobility test, get up and go test, and 6-min walk test). A physical therapist applied the 10/50/10 protocol for Russian stimulation, stimulating the quadriceps and tibialis anterior muscles separately; simultaneously, the participants performed isometric exercise at a frequency of three sessions per week for 12 weeks. Descriptive statistics, the paired-sample t-test, and the χ-test were performed. The study included 25 participants (96% women, mean age 65.2±5.5 years). After the intervention, there was a significant improvement in the strength of the quadriceps (~30%) and tibialis anterior (~40%) muscles as well as the results of the balance (Tinetti 22%, Berg 10%) and mobility (get up and go 25%, 6-min distance 20%) tests. On the basis of the improvements in the Tinetti and Berg scores, significantly fewer participants were classified as being at increased risk for falls. The muscle strength correlated with several clinical evaluation results, but not with the Tinetti test score. Russian stimulation plus isometric exercise improves strength, balance, and mobility, which may decrease the fall risk.

Serotonergic mechanisms involved in antidepressant-like responses evoked by GLT-1 blockade in rat infralimbic cortex.

Novel fast-acting antidepressant strategies, such as ketamine and deep brain stimulation, enhance glutamatergic neurotransmission in medial prefrontal cortex (mPFC) regions via AMPA receptor (AMPA-R) activation. We recently reported that the regionally-selective blockade of the glial glutamate transporter-1 (GLT-1) by dihydrokainic acid (DHK) microinfusion in rat infralimbic cortex (IL), the most ventral part of the mPFC, evoked immediate (10 min) antidepressant-like responses, which involved AMPA-R activation and were associated to increased serotonin (5-hydroxytryptamine, 5-HT) release. Given the reciprocal connectivity between the mPFC and the serotonergic dorsal raphe nucleus (DR), here we examined the serotoninergic mechanisms involved in the reported antidepressant-like responses of DHK microinfusion. First, we show that antidepressant-like responses evoked by IL application of DHK and citalopram are mediated by local 5-HT1A receptors (5-HT1A-R), since they are cancelled by previous IL WAY100635 microinfusion. Second, IL DHK microinfusion increases excitatory inputs onto DR, as shown by an increased glutamate and 5-HT release in DR and by a selective increase of c-Fos expression in DR 5-HT neurons, not occurring in putative GABAergic neurons. This view is also supported by an increased 5-HT release in ventral hippocampus following IL DHK microinfusion. Interestingly, antidepressant-like responses evoked by IL DHK lasted for 2 h and could be prolonged for up to 24 h by attenuating self-inhibitory effects via 5-HT1A autoreceptors. In contrast, the antidepressant-like effects of S-AMPA microinfusion in IL were short-lasting. Together, our results further support a prominent role of the IL-DR pathway and of ascending 5-HT pathways in mediating antidepressant-like responses evoked by glutamatergic mechanisms.