Impact of 1-Year Supplementation with High-Rich Docosahexaenoic Acid (DHA) on Clinical Variables and Inflammatory Biomarkers in Pediatric Cystic Fibrosis: A Randomized Double-Blind Controlled Trial.

A randomized, double-blind, and placebo-controlled study was conducted to assess the effect of dietary supplementation with high-rich docosahexaenoic acid (DHA) (Tridocosahexanoin-AOX® 70%) at 50 mg/kg/day in pediatric patients with cystic fibrosis (CF) as compared with placebo. The duration of supplementation was 12 months. A total of 22 patients were included, with 11 in the DHA group and 11 in the placebo group. The mean age was 11.7 years. The outcome variables were pulmonary function, exacerbations, sputum cellularity, inflammatory biomarkers in sputum and peripheral blood, and anthropometric variables. In the DHA group, there was a significant increase in FVC (p = 0.004) and FVE1 expressed in liters (p = 0.044) as compared with placebo, and a lower median number of exacerbations (1 vs. 2). Differences in sputum cellularity (predominantly neutrophilic), neutrophilic elastase, and sputum and serum concentrations of resolvin D1 (RvD1), interleukin (IL)-8 (IL-8), and tumor necrosis factor alpha (TNF-α) between the study groups were not found. Significant increases in weight and height were also observed among DHA-supplemented patients. The administration of the study product was safe and well tolerated. In summary, the use of a highly concentrated DHA supplement for 1 year as compared with placebo improved pulmonary function and reduced exacerbations in pediatric CF.

Protocol for stimulating specific rodent limb receptive fields while recording in vivo somatosensory-evoked activity.

Studies on sensory information processing typically focus on whisker-related tactile information, overlooking the question of how sensory inputs from other body areas are processed at cortical levels. Here, we present a protocol for stimulating specific rodent limb receptive fields while recording in vivo somatosensory-evoked activity. We describe steps for localizing cortical-hindlimb coordinates using acute peripheral stimulation, electrode placement, and the application of electrical stimulation. This protocol overcomes the challenge of inducing a reproducible and consistent stimulation of specific limbs. For complete details on the use and execution of this protocol, please refer to Miguel-Quesada et al.1.

Increased excitability and reduced GABAergic levels in somatosensory cortex under chronic spinal cord injury.

The complete or partial damage of ascending somatosensory pathways produced by a spinal cord injury triggers changes in the somatosensory cortex consisting in a functional expansion of activity from intact cortical regions towards deafferented ones, a process known as cortical reorganization. However, it is still unclear whether cortical reorganization depends on the severity of the spinal cord damage or if a spinal cord injury always leads to a similar cortical reorganization process in the somatosensory cortex. To answer these open questions in the field, we obtained longitudinal somatosensory evoked responses from bilateral hindlimb and forelimb cortex from animals with chronic full-transection or contusive spinal cord injury at thoracic level (T9-T10) to induce sensory deprivation of hindlimb cortex while preserving intact the forelimb cortex. Electrophysiological recordings from the four locations were obtained before lesion and weekly for up to 4 weeks. Our results show that cortical reorganization depends on the type of spinal cord injury, which tends to be more bilateral in full transection while is more unilateral in the model of contusive spinal cord injury. Moreover, in full transection of spinal cord, the deafferented and intact cortex exhibited similar increments of somatosensory evoked responses in both models of spinal cord injury - a feature observed in about 80% of subjects. The other 20% were unaffected by the injury indicating that cortical reorganization does not undergo in all subjects. In addition, we demonstrated an increased probability of triggered up-states in animals with spinal cord injury. This data indicates increased cortical excitability that could be proposed as a new feature of cortical reorganization. Finally, decreased levels of GABA marker GAD67 across cortical layers were only found in those animals with increased somatosensory evoked responses, but not in the unaffected population. In conclusion, cortical reorganization depends on the types of spinal cord injuries, and suggest that the phenomenon is strongly determined by cortical circuits. Moreover, changes in GABAergic transmission at the deprived cortex may be considered one of the mechanisms underlying the process of cortical reorganization and increased excitability.

Astrocytes adjust the dynamic range of cortical network activity to control modality-specific sensory information processing.

Cortical neuron-astrocyte communication in response to peripheral sensory stimulation occurs in a topographic-, frequency-, and intensity-dependent manner. However, the contribution of this functional interaction to the processing of sensory inputs and consequent behavior remains unclear. We investigate the role of astrocytes in sensory information processing at circuit and behavioral levels by monitoring and manipulating astrocytic activity in vivo. We show that astrocytes control the dynamic range of the cortical network activity, optimizing its responsiveness to incoming sensory inputs. The astrocytic modulation of sensory processing contributes to setting the detection threshold for tactile and thermal behavior responses. The mechanism of such astrocytic control is mediated through modulation of inhibitory transmission to adjust the gain and sensitivity of responding networks. These results uncover a role for astrocytes in maintaining the cortical network activity in an optimal range to control behavior associated with specific sensory modalities.

Normal Cortical Myelination in Galectin-4-Deficient Mice.

Myelin, critical for the correct function of the nervous system, is organized in different patterns that can include long non-myelinated axonal segments. How myelin patterning is regulated remains unexplained. The carbohydrate-binding protein galectin-4 (Gal-4) influences oligodendrocyte differentiation in vitro and is associated with non-myelinable axon segments (NMS) in cultured neurons. In consequence, Gal-4 has been proposed as a myelin patterning regulator, although no in vivo studies have corroborated this hypothesis. We used Gal-4-deficient mice (Lgals4-KO) to study the role of Gal-4 in cortical myelination in vivo. We show that cultured neurons of Lgals4-KO mice form NMS that are regulated as in control neurons. In addition, oligodendrocyte/myelin markers expression measured by biochemical and immunochemical means, and cortical myelin microstructure studied by in-depth image analysis appear unaltered in these animals. Consistently, myelin displays an essentially normal function assessed by in vivo electrophysiology and locomotion analyses. In conclusion, cortical myelin of Lgals4-KO mice does not show any significant defect in composition, organization or function, pointing to a negligible role of Gal-4 in myelination in vivo or, as discussed, to unknown mechanisms that compensate its absence.

Cortical layer-specific modulation of neuronal activity after sensory deprivation due to spinal cord injury.

Cortical areas have the capacity of large-scale reorganization following sensory deafferentation. However, it remains unclear whether this phenomenon is a unique process that homogeneously affects the entire deprived cortical region or whether it is susceptible to changes depending on neuronal networks across distinct cortical layers. Here, we studied how the local circuitry within each layer of the deafferented cortex forms the basis for neuroplastic changes after immediate thoracic spinal cord injury (SCI) in anaesthetized rats. In vivo electrophysiological recordings from deafferented hindlimb somatosensory cortex showed that SCI induces layer-specific changes mediating evoked and spontaneous activity. In supragranular layer 2/3, SCI increased gamma oscillations and the ability of these neurons to initiate up-states during spontaneous activity, suggesting an altered corticocortical network and/or intrinsic properties that may serve to maintain the excitability of the cortical column after deafferentation. On the other hand, SCI enhanced the infragranular layers' ability to integrate evoked sensory inputs leading to increased and faster neuronal responses. Delayed evoked response onsets were also observed in layer 5/6, suggesting alterations in thalamocortical connectivity. Altogether, our data indicate that SCI immediately modifies the local circuitry within the deafferented cortex allowing supragranular layers to better integrate spontaneous corticocortical information, thus modifying column excitability, and infragranular layers to better integrate evoked sensory inputs to preserve subcortical outputs. These layer-specific neuronal changes may guide the long-term alterations in neuronal excitability and plasticity associated with the rearrangements of somatosensory networks and the appearance of central sensory pathologies usually associated with spinal cord injury. KEY POINTS: Sensory stimulation of forelimb produces cortical evoked responses in the somatosensory hindlimb cortex in a layer-dependent manner. Spinal cord injury favours the input statistics of corticocortical connections between intact and deafferented cortices. After spinal cord injury supragranular layers exhibit better integration of spontaneous corticocortical information while infragranular layers exhibit better integration of evoked sensory stimulation. Cortical reorganization is a layer-specific phenomenon.

TLR4 pathway impairs synaptic number and cerebrovascular functions through astrocyte activation following traumatic brain injury.

BACKGROUND AND PURPOSE: Activation of astrocytes contributes to synaptic remodelling, tissue repair and neuronal survival following traumatic brain injury (TBI). The mechanisms by which these cells interact to resident/infiltrated inflammatory cells to rewire neuronal networks and repair brain functions remain poorly understood. Here, we explored how TLR4-induced astrocyte activation modified synapses and cerebrovascular integrity following TBI. EXPERIMENTAL APPROACH: To determine how functional astrocyte alterations induced by activation of TLR4 pathway in inflammatory cells regulate synapses and neurovascular integrity after TBI, we used pharmacology, genetic approaches, live calcium imaging, immunofluorescence, flow cytometry, blood-brain barrier (BBB) integrity assessment and molecular and behavioural methods. KEY RESULTS: Shortly after a TBI, there is a recruitment of excitable and reactive astrocytes mediated by TLR4 pathway activation with detrimental effects on post-synaptic density-95 (PSD-95)/vesicular glutamate transporter 1 (VGLUT1) synaptic puncta, BBB integrity and neurological outcome. Pharmacological blockage of the TLR4 pathway with resatorvid (TAK-242) partially reversed many of the observed effects. Synapses and BBB recovery after resatorvid administration were not observed in IP3 R2-/- mice, indicating that effects of TLR4 inhibition depend on the subsequent astrocyte activation. In addition, TBI increased the astrocytic-protein thrombospondin-1 necessary to induce a synaptic recovery in a sub-acute phase. CONCLUSIONS AND IMPLICATIONS: Our data demonstrate that TLR4-mediated signalling, most probably through microglia and/or infiltrated monocyte-astrocyte communication, plays a crucial role in the TBI pathophysiology and that its inhibition prevents synaptic loss and BBB damage accelerating tissue recovery/repair, which might represent a therapeutic potential in CNS injuries and disorders.

Immunologic Characteristics of Nonmelanoma Skin Cancers: Implications for Immunotherapy.

In this review, we summarize the immunology of nonmelanoma skin cancers (NMSCs) and the clinical data with immunotherapy in this heterogeneous group of cancers that include basal cell carcinoma (BCC), cutaneous squamous cell carcinoma (CSCC), and Merkel cell carcinoma (MCC). NMSCs are exceedingly common, and their treatment consumes substantial health care resources. Annual global mortality from NMSCs is comparable to that from malignant melanoma. Although the majority of NMSCs are localized at diagnosis and are treated effectively with surgery, metastases (nodal and distant) can sometimes arise and require systemic therapy. Given the success of immunotherapy in treating cutaneous melanoma, there has been an increasing interest in studying the immunology of NMSCs. Immunocompromised patients have a substantially higher risk of developing NMSCs (particularly CSCC and MCC), suggesting a role of the immune system in the pathogenesis of these cancers. Similar to cutaneous melanoma, the pathogenesis of BCC, CSCC, and virus-negative MCC is related to DNA damage from ultraviolet radiation exposure, and these cancers have a very high tumor mutational burden, which likely results in higher levels of tumor neoantigens that may be targets for the immune system. Viral antigens in virus-positive MCC are also strongly immunogenic. Emerging data from clinical trials of immune checkpoint inhibitors in NMSCs look very promising and are rapidly changing the treatment landscape of these cancers. Specifically, pembrolizumab and avelumab are U.S. Food and Drug Administration-approved for treatment of metastatic MCC and cemiplimab for metastatic CSCC. Several ongoing trials are investigating novel immunotherapies (monotherapies as well as combination) for treatment of NMSCs.

Russian sturgeon cultured in a subtropical climate shows weaken innate defences and a chronic stress response.

Russian sturgeon (Acipenser gueldenstaedtii) has been successfully farmed in Uruguay for the past ten years. However, during the Uruguayan summer fish endure high water temperatures and increased bacterial infections that threaten aquaculture. Our understanding of sturgeon's immune system and its interplay with environmental factors like temperature is almost unknown. This study analysed the way in which seasonal variations affect enzymatic blood components of Russian sturgeon's innate defences, including the serum alternative complement pathway (ACP), ceruloplasmin (Cp) and lysozyme activities. Results showed that summertime conditions in the farm altered these defences in different ways, inducing a significant decrease in ACP and Cp, and an increase in lysozyme. In addition, serum levels of total protein and cortisol decreased in summer, suggesting a chronic stress response was induced in parallel. Subsequently, we analysed whether the increase in water river temperature during summer could account for the observed results. To that end, we acclimated juvenile sturgeons to mild (18 °C) or warm (24 °C) temperatures for 37 days. Like in summer, sturgeons exposed to 24 °C showed lower levels of serum ACP, Cp and total proteins, together with a progressive decrease in body weight and increased fish mortality. Administration of an immunostimulant containing Se and Zn slightly reverted the temperature-induced effects on sturgeon's defences. Altogether, our study provides novel data on various physiological parameters of the Russian sturgeon and highlights the impact warm temperature has on stress and innate immunity in this chondrostean fish.

Dual Cortical Plasticity After Spinal Cord Injury.

During cortical development, plasticity reflects the dynamic equilibrium between increasing and decreasing functional connectivity subserved by synaptic sprouting and pruning. After adult cortical deafferentation, plasticity seems to be dominated by increased functional connectivity, leading to the classical expansive reorganization from the intact to the deafferented cortex. In contrast, here we show a striking "decrease" in the fast cortical responses to high-intensity forepaw stimulation 1-3 months after complete thoracic spinal cord transection, as evident in both local field potentials and intracellular in vivo recordings. Importantly, this decrease in fast cortical responses co-exists with an "increase" in cortical activation over slower post-stimulus timescales, as measured by an increased forepaw-to-hindpaw propagation of stimulus-triggered cortical up-states, as well as by the enhanced slow sustained depolarization evoked by high-frequency forepaw stimuli in the deafferented hindpaw cortex. This coincidence of diminished fast cortical responses and enhanced slow cortical activation offers a dual perspective of adult cortical plasticity after spinal cord injury.