A potential therapeutic target: The role of neutrophils in the central nervous system.

Neutrophils play a critical role in immune defense as the first recruited and most abundant leukocytes in the innate immune system. As such, regulation of neutrophil effector functions have strong implications on immunity. These cells display a wide heterogeneity of function, including both inflammatory and immunomodulatory roles. Neutrophils commonly infiltrate the central nervous system (CNS) in response to varied pathological conditions. There is still little understanding of the role these cells play in the CNS in such conditions. In the present review, we will summarize what is known of neutrophil's role in cancer and Alzheimer's disease (AD), with a focus on highlighting the gaps in our understanding.

Neutrophil modulation of behavior and cognition in health and disease: The unexplored role of an innate immune cell.

Behavior and cognition are multifaceted processes influenced by genetics, synaptic plasticity, and neuronal connectivity. Recent reports have demonstrated that peripheral inflammation and peripheral immune cells play important roles in the preservation and deterioration of behavior/cognition under various conditions. Indeed, several studies show that the activity of peripheral immune cells can be critical for normal cognitive function. Neutrophils are the most abundant immune cells in the mammalian system. Their activation is critical to the initiation of the inflammatory process and critical for wound healing. Neutrophils are the first cells to be activated and recruited to the central nervous system in both injury and disease. However, our understanding of the role these cells play in behavior and cognition is limited. The present review will summarize what is currently known about the effect the activation of these cells has on various behaviors and cognitive processes.

AAV vectors accumulate in the pineal gland after injections into the brain or spinal cord.

AAV vectors are being used extensively for gene-modifying therapies for neurological disorders. Here, we report the surprising discovery that injections of different AAVs into the brain, spinal cord, or cerebrospinal fluid (CSF) lead to robust transduction of cells in the pineal gland. We document transduction of cells in the pineal gland following focal injections of AAV2/9-shPTEN-zsGreen into the sensorimotor or hippocampus of rats and injections of AAV2/Cre into the spinal cord of transgenic mice with a stop-flox tdT reporter. Pineal transduction was evident even when AAV2/Cre injections were made into the lumbar spinal cord many millimeters distant from the pineal gland. Immunostaining with antibodies for cell types in the pineal gland revealed that pinealocytes were transduced. Pineal transduction was also observed with intracerebroventricular (i.c.v.) injections of AAV2/9-shPTEN-zsGreen, suggesting that pineal transduction following focal injections of AAV into CNS parenchyma may be caused by diffusion of the vector from the injection sites into the CSF and then accumulation in the pineal gland. Together, these findings suggest the need for vigilance for functional consequences and possible adverse effects of off-target accumulation of therapeutic AAVs in the pineal gland and AAV-driven expression of therapeutic cargos in pinealocytes.

Neutrophil Enzyme Myeloperoxidase Modulates Neuronal Response in a Model of Subarachnoid Hemorrhage by Venous Injury.

Background and Purpose: Aneurysmal subarachnoid hemorrhage (SAH) is associated with the development of delayed cognitive deficits. Neutrophil infiltration into the central nervous system is linked to the development of these deficits after SAH. It is however unclear how neutrophil activity influences central nervous system function in SAH. The present project aims to elucidate which neutrophil factors mediate central nervous system injury and cognitive deficits after SAH. Methods: Using a murine model of SAH and mice deficient in neutrophil effector functions, we determined which neutrophil effector function is critical to the development of deficits after SAH. In vivo and in vitro techniques were used to investigate possible pathways of neutrophils effect after SAH. Results: Our results show that mice lacking functional MPO (myeloperoxidase), a neutrophil enzyme, lack both the meningeal neutrophil infiltration (wild type, sham 872 cells/meninges versus SAH 3047, P=0.023; myeloperoxidase knockout [MPOKO], sham 1677 versus SAH 1636, P=NS) and erase the cognitive deficits on Barnes maze associated with SAH (MPOKO sham versus SAH, P=NS). The reintroduction of biologically active MPO, and its substrate hydrogen peroxide (H2O2), to the cerebrospinal fluid of MPOKO mice at the time of hemorrhage restores the spatial memory deficit observed after SAH (time to goal box MPOKO sham versus MPOKO+MPO/H2O2, P=0.001). We find evidence of changes in neurons, astrocytes, and microglia with MPO/H2O2 suggesting the effect of MPO may have complex interactions with many cell types. Neurons exposed to MPO/H2O2 show decreased calcium activity at baseline and after stimulation with potassium chloride. Although astrocytes and microglia are affected, changes seen in astrocytes are most consistent with inflammatory changes that likely affect neurons. Conclusions: These results implicate MPO as a mediator of neuronal dysfunction in SAH through its effect on both neurons and glia. These results show that, in SAH, the activity of innate immune cells in the meninges modulates the activity and function of the underlying brain tissue.

Microbiological and Physicochemical Characteristics of Three Types of "Soumbara" from Seeds of African Locust Bean in Korhogo Markets, Côte d'Ivoire.

"Soumbara" is a fermented product sold in the markets of several West African countries. In the markets, it is sold in several formats (granulated, powder, and paste). The objective of this study was to evaluate the microbiological and physicochemical characteristics of these three types of "Soumbara" sold in the Korhogo markets. For this purpose, a preliminary survey followed by a sampling of 54 samples of "Soumbara" was carried out. The microorganism load count was carried out according to microbiological standards. The pH, titratable acidity, and moisture content were measured, respectively, with a pH meter, by dosing with sodium hydroxide solution and by differential weighing after passing the sample through the oven. The pH of the different samples is around 6. The moisture content is higher in "Soumbara" paste (20-24.7%) than in powdered (7.3-9.3%) and granulated (8.6-10.7%) "Soumbara." The acidity rates are between 0.07 and 0.13%, 0.2 and 0.3%, and 0.08 and 0.1%, respectively, for the granulated, powder, and paste types. Mesophilic aerobic germ loads (6.17-8.38 log10 cfu/g) for all three types of "Soumbara" are above the standard. Total coliform (1.13-2.96 log10 cfu/g), mould (0.86-2.52 log10 cfu/g), and yeast (0.33-1.53 log10 cfu/g) loads are below standard. The microbiological quality of the three types of "Soumbara" is unsatisfactory. Overall, "Soumbara" powder is the most contaminated, followed by granulated and paste "Soumbara." "Soumbara" must be added during culinary preparations in order to avoid possible public health problems.

Activated Microglia in the Rat Spinal Cord Following Peripheral Axon Injury Promote Glial and Neuronal Plasticity Which is Necessary for Long-Term Neuronal Survival.

Following the transection of peripheral sympathetic preganglionic axons comprising the cervical sympathetic trunk (CST), we observe robust glial and neuronal plasticity at 1 week post-injury in the rat spinal cord intermediolateral cell column (IML), which houses the injured parent neuronal cell bodies. This plasticity contributes to neuroprotection, as no neuronal loss in the IML is present at 16 weeks post-injury. Here, we administered the antibiotic minocycline or vehicle (VEH) daily for 1 week after CST transection to investigate the role of activated microglia in IML glial and neuronal plasticity and subsequent neuronal survival. At 1 week post-injury, minocycline treatment did not alter microglia number in the IML, but led to a dampened microglia activation state. In addition, the increases in oligodendrocyte (OL) lineage cells and activated astrocytes following injury in VEH rats were attenuated in the minocycline-treated rats. Further, the normal downregulation of choline acetyltransferase (ChAT) in the injured neurons was blunted. At 16 weeks post-injury, fewer ChAT+ neurons were present in the minocycline-treated rats, suggesting that activated microglia together with the glial and neuronal plasticity at 1 week post-injury contribute to the long-term survival of the injured neurons. These results provide evidence for beneficial crosstalk between activated microglia and neurons as well as other glial cells in the cord following peripheral axon injury, which ultimately leads to neuroprotection. The influences of microglia activation in promoting neuronal survival should be considered when developing therapies to administer minocycline for the treatment of neurological pathologies.

Quality of maternal and newborn care in limited-resource settings: a facility-based cross-sectional study in Burkina Faso and Côte d'Ivoire.

OBJECTIVE: To assess and compare the quality of intrapartum and immediate postpartum care across levels of healthcare in Burkina Faso and Côte d'Ivoire using validated process indicators. DESIGN: Health facility-based cross-sectional study with direct observation of healthcare workers' practices while caring for mother-newborn pairs during intrapartum and immediate postpartum periods. SETTING: Primary healthcare facilities and their corresponding referral hospitals in the Central-North region in Burkina Faso and the Agneby-Tiassa-Mé region in Côte d'Ivoire. PARTICIPANTS: Healthcare providers who care for mother-newborn pairs during intrapartum and immediate postpartum periods, the labouring women and their newborns after childbirth. MAIN OUTCOME MEASURES: Adherence to essential best practices (EBPs) at four pause points in each birth event and the overall quality score based on the level of adherence to the set of EBPs observed for a selected pause point. RESULTS: A total of 532 and 627 labouring women were included in Burkina Faso and Côte d'Ivoire, respectively. Overall, the compliance with EBPs was insufficient at all the four pause points, even though it varied widely from one EBP to another. The adherence was very low with respect to hand hygiene practices: the care provider wore sterile gloves for vaginal examination in only 7.96% cases (95% CI 5.66% to 11.06%) in Burkina Faso and the care provider washed hands before examination in 6.71% cases (95% CI 3.94% to 11.20%) in Côte d'Ivoire. The adherence was very high with respect to thermal management of newborns in both countries (>90%). The overall mean quality scores were consistently higher in referral hospitals in Burkina Faso at all pause points excluding immediate post partum. CONCLUSIONS: Women delivering in healthcare facilities do not always receive proven EBPs needed to prevent poor childbirth outcomes. There is a need for quality improvement interventions.

AAVshRNA-mediated PTEN knockdown in adult neurons attenuates activity-dependent immediate early gene induction.

Genetic deletion or knockdown of PTEN enables regeneration of CNS axons, enhances sprouting of intact axons after injury, and induces de novo growth of uninjured adult neurons. It is unknown, however how PTEN deletion in mature neurons alters neuronal physiology. As a first step to address this question, we used immunocytochemistry for activity-dependent markers to assess consequences of PTEN knockdown in cortical neurons and granule cells of the dentate gyrus. In adult rats that received unilateral intra-cortical injections of AAV expressing shRNA against PTEN, immunostaining for c-fos under resting conditions (home cage, HC) and after 1 h of exploration of a novel enriched environment (EE) revealed no hot spots of c-fos expression that would suggest abnormal activity. Counts revealed similar numbers of c-fos positive neurons in the area of PTEN deletion vs. homologous areas in the contralateral cortex in the HC and similar induction of c-fos with EE. However, IEG induction in response to high frequency stimulation (HFS) of the cortex was attenuated in areas of PTEN deletion. In rats with AAVshRNA-mediated PTEN deletion in the dentate gyrus, induction of the IEGs c-fos and Arc with HFS of the perforant path was abrogated in areas of PTEN deletion. Immunostaining using phosphospecific antibodies for phospho-S6 (a downstream marker for mTOR activation) and phospho-ERK1/2 revealed abrogation of S6 phosphorylation in PTEN-deleted areas but preserved activation of phosphorylation of ERK1/2. SIGNIFICANCE STATEMENT: Deletion or knockdown of the tumor suppressor gene PTEN enables regenerative growth of adult CNS axons after injury, which is accompanied by enhanced recovery of function. Consequently, PTEN represents a potential target for therapeutic interventions to enhance recovery after CNS injury. Here we show that activity-dependent IEG induction is attenuated in PTEN-depleted neurons. These findings raise the intriguing possibility that functional recovery due to regenerative growth may be limited by the disruption of plasticity-related signaling pathways, and that recovery might be enhanced by restoring PTEN expression after regenerative growth has been achieved.

Late mortality after cardiac interventions over 10-year period in two Cameroonian government-owned hospitals.

BACKGROUND: Cardiac surgery is a growing activity in Sub-Saharan Africa, however, data related to long-term mortality are scarce. We aimed to analyze outcome data of cardiac interventions in two hospitals in Cameroon over 10 years' period. METHODS: we conducted a retrospective analytical and descriptive study at the Douala General Hospital and Yaoundé General Hospital. All patients operated between January 2007 and December 2017, or their families were contacted by phone between January and April 2018 for a free of charges medical examination. RESULTS: Of a total of 98 patients operated during the study period, 8 (8.2%) were lost to follow-up. Finally, 90 patients [49 (54.4%) women and 41 (45.6%)] men were included. The mean age was 49±22 years (range, 13-89 years). The surgical indications were valvular heart diseases in 37 (41.1%) cases, congenital heart diseases in 11 (12.2%) cases, chronic constrictive pericarditis in 4 (4.4%) cases, and intra cardiac tumor in 1 (1.1%) case. Valve replacement was the most common type of surgery carried out in 37 (41.1%) cases-mostly with mechanical prosthesis. Pacemaker-mostly dual-chambers were implanted in 36 (40.0%) patients. The median follow-up was 26 months. The overall late mortality was 5.7%, and the overall survival rates at 5 and 10 years were 95.5% and 94.4% respectively. The overall survival rates at 5 and 10 years for mechanical valve prosthesis were 93.3% and 90% respectively. The survival at 10 years was 100% for patients with bioprosthesis. The survival rates at 10 years were 94.1% and 100% respectively for dual and single chamber pacemaker. CONCLUSIONS: Long-term outcome of cardiac surgery in hospitals in Cameroon are acceptable with low mortality rate. However, outcome metrics beyond mortality should be implemented for a prospective data collection.

Retrograde influences of SCG axotomy on uninjured preganglionic neurons.

There is evidence that neuronal injury can affect uninjured neurons in the same neural circuit. The overall goal of this study was to understand the effects of peripheral nerve injury on uninjured neurons located in the central nervous system (CNS). As a model, we examined whether axotomy (transection of postganglionic axons) of the superior cervical ganglion (SCG) affected the uninjured, preganglionic neurons that innervate the SCG. At 7 days post-injury a reduction in choline acetyltransferase (ChAT) and synaptophysin immunoreactivity in the SCG, both markers for preganglionic axons, was observed, and this reduction persisted at 8 and 12 weeks post-injury. No changes were observed in the number or size of the parent cell bodies in the intermediolateral cell column (IML) of the spinal cord, yet synaptic input to the IML neurons was decreased at both 8 and 12 weeks post-injury. In order to understand the mechanisms underlying these changes, protein levels of brain-derived neurotrophic factor (BDNF) and tyrosine receptor kinase B (TrkB) were examined and reductions were observed at 7 days post-injury in both the SCG and spinal cord. Taken together these results suggest that axotomy of the SCG led to reduced BDNF in the SCG and spinal cord, which in turn influenced ChAT and synaptophysin expression in the SCG and also contributed to the altered synaptic input to the IML neurons. More generally these findings provide evidence that the effects of peripheral injury can cascade into the CNS and affect uninjured neurons.

Incidence, characteristics and prognosis of acute kidney injury in Cameroon: a prospective study at the Douala General Hospital.

OBJECTIVE: There are limited data on AKI in sub-Saharan Africa. We aim to determine the incidence, characteristics and prognosis of AKI in Cameroon. PATIENTS AND METHODS: A prospective study including all consenting acute admissions in the internal medicine and the ICU of a tertiary referral hospital in Cameroon from January 2015 to June 2016. Serum creatinine assay was done on admission, days 2 and 7 to diagnose AKI. For patients with AKI, serum creatinine was done on discharge, days 30, 60 and 90. AKI was defined according to the modified KDIGO 2012 criteria as an increase or decrease in serum creatinine of 3 mg/l or greater, or an increase of 50% or more from the reference value obtained at admission or the known baseline value. AKI severity was graded using KDIGO2012 criteria. Outcome measures were renal recovery, mortality and causes of death. Renal recovery was complete if serum creatinine between the first 90 days was less than baseline or reference, partial if less than diagnosis but not baseline or reference, no-recovery if creatinine did not decrease or if the patient remained on dialysis. RESULTS: Of the 2402 patients included, 536 developed AKI giving a global incidence of 22.3% and annual incidence of 15 per 100 patients-years. Of the 536 patients with AKI, 43.3% were at stage 3, 54.7% were males, median age was 56 years. Pre-renal AKI (61.4%) and acute tubular necrosis (28.9%) were the most frequent forms. Main etiologies were sepsis (50.4%) and volume depletion (31.6%). Renal outcome was unknown in 34% of patients. Of the 354 patients with known renal function at 3 months, 84.2% recovered completely, 14.7% partially and 1.1% progressed to CKD. Global mortality rate was 36.9% mainly due to sepsis. CONCLUSIONS: AKI is frequent in our setting, mainly due to sepsis and hypovolemia. It carries a poor prognosis.

Outcome of permanent vascular access for haemodialysis in patients with end-stage renal disease in Cameroon: results from the pilot experience of the Douala general hospital.

Background Chronic Kidney disease is a major health problem in the world. Native arteriovenous Fistula (AVF) is well established as the best vascular access for haemodialysis. Little is known about the outcome of AVF in sub-Saharan Africa. We aim to analyze the outcome of patients undergoing AVF creation during the pilot program established at the Douala general hospital (DGH). Method This was hospital-based, longitudinal study with a retrospective phase (April 2010-January 2014) and a prospective phase (January 2014-April 2014). All consecutive patients operated for AVF creation were included in this study. Socio-demographics data, functionality, and complications were analyzed. Results Eighty-one patients including 52 men were enrolled in this study (49 prospectively and 32 retrospectively). The mean age was 52, 3 years (range 18-81 years). Hypertension (66, 7%), diabetes (17, 3%), and HIV (8, 6%) were the most observed co-morbidities. About 96.3% of AVF were native and 3.7% were prosthetic graft. Radiocephalic AVF was performed at a rate of 77.8%. The primary function rate was 97.7% and the mean follow-up period 43.4 weeks. The overall rate of complications was 44.4% of whom 30.5% were early, 30.5% secondary, and 39% lasted. The treatment of these complications was conservative in 48.7% of cases. Conclusions The results of the pilot program of AVF creation at the DGH are encouraging. However, the sustainability of this project requires human capacity building.

Increased Cx32 expression in spinal cord TrkB oligodendrocytes following peripheral axon injury.

Following injury to motor axons in the periphery, retrograde influences from the injury site lead to glial cell plasticity in the vicinity of the injured neurons. Following the transection of peripherally located preganglionic axons of the cervical sympathetic trunk (CST), a population of oligodendrocyte (OL) lineage cells expressing full length TrkB, the cognate receptor for brain derived neurotrophic factor (BDNF), is significantly increased in number in the spinal cord. Such robust plasticity in OL lineage cells in the spinal cord following peripheral axon transection led to the hypothesis that the gap junction communication protein connexin 32 (Cx32), which is specific to OL lineage cells, was influenced by the injury. Following CST transection, Cx32 expression in the spinal cord intermediolateral cell column (IML), the location of the parent cell bodies, was significantly increased. The increased Cx32 expression was localized specifically to TrkB OLs in the IML, rather than other cell types in the OL cell lineage, with the population of Cx32/TrkB cells increased by 59%. Cx32 expression in association with OPCs was significantly decreased at one week following the injury. The results of this study provide evidence that peripheral axon injury can differentially affect the gap junction protein expression in OL lineage cells in the adult rat spinal cord. We conclude that the retrograde influences originating from the peripheral injury site elicit dramatic changes in the CNS expression of Cx32, which in turn may mediate the plasticity of OL lineage cells observed in the spinal cord following peripheral axon injury.

Distribution and phenotype of TrkB oligodendrocyte lineage cells in the adult rat spinal cord.

The distribution and phenotype of a previously undescribed population of nonneuronal cells in the intact spinal cord that expresses TrkB, the cognate receptor for brain derived neurotrophic factor (BDNF) and neurotrophin 4 (NT-4), were characterized by examining the extent of co-localization of TrkB with NG2, which identifies oligodendrocyte progenitors (OPCs) or CC1, a marker for mature oligodendrocytes (OLs). All TrkB nonneuronal cells expressed Olig2, confirming their role in the OL lineage. Similar to OPCs and OLs, TrkB cells resided in gray and white matter of the spinal cord in similar abundance. Less than 2% of TrkB cells expressed NG2, while over 80% of TrkB cells in the adult spinal cord co-expressed CC1. Most OPCs did not express detectable levels of TrkB, however a small OPC pool (~5%) showed TrkB immunoreactivity. The majority of mature OLs (~65%) expressed TrkB, but a population of mature OLs (~36%) did not express TrkB at detectable levels, and 17% of TrkB nonneuronal cells did not express NG2 or CC1. Approximately 20% of the TrkB nonneuronal population in the ventral horn resided in close proximity to motor neurons and were categorized as perineuronal. We conclude that TrkB is expressed by several pools of OL lineage cells in the adult spinal cord. These findings are important in understanding the neurotrophin regulation of OL lineage cells in the adult spinal cord.

Transection of preganglionic axons leads to CNS neuronal plasticity followed by survival and target reinnervation.

The goals of the present study were to investigate the changes in sympathetic preganglionic neurons following transection of distal axons in the cervical sympathetic trunk (CST) that innervate the superior cervical ganglion (SCG) and to assess changes in the protein expression of brain derived neurotrophic factor (BDNF) and its receptor TrkB in the thoracic spinal cord. At 1 week, a significant decrease in soma volume and reduced soma expression of choline acetyltransferase (ChAT) in the intermediolateral cell column (IML) of T1 spinal cord were observed, with both ChAT-ir and non-immunoreactive neurons expressing the injury marker activating transcription factor 3. These changes were transient, and at later time points, ChAT expression and soma volume returned to control values and the number of ATF3 neurons declined. No evidence for cell loss or neuronal apoptosis was detected at any time point. Protein levels of BDNF and/or full length TrkB in the spinal cord were increased throughout the survival period. In the SCG, both ChAT-ir axons and ChAT protein remained decreased at 16 weeks, but were increased compared to the 10 week time point. These results suggest that though IML neurons show reduced ChAT expression and cell volume at 1 week following CST transection, at later time points, the neurons recovered and exhibited no significant signs of neurodegeneration. The alterations in BDNF and/or TrkB may have contributed to the survival of the IML neurons and the recovery of ChAT expression, as well as to the reinnervation of the SCG.

Transient changes in spinal cord glial cells following transection of preganglionic sympathetic axons.

Following peripheral nerve injury, retrograde signals originating from the injury site may activate intrinsic factors in the injured neurons, possibly leading to regenerative growth. Retrograde influences from peripheral injury sites may lead to the activation of glial cells in the vicinity of the centrally located cell bodies of the injured neurons. Few studies have examined changes in the spinal cord intermediolateral cell column (IML), which houses sympathetic preganglionic cell bodies, following injury to distal axons in the cervical sympathetic trunk (CST). The goal of the present study was to determine if transection of the CST results in plasticity in glial cells in the IML. At 1 day following injury, changes in the expression of microglial marker Iba1 were observed and the typical oligodendrocyte-neuronal relationship was altered. By 7 days, astrogliosis, microglial aggregation, and increased numbers of oligodendrocytes, as well as enhanced glial-glial and glial-neuronal relationships were present. The majority of cases were similar to controls at 3 weeks following injury and no changes were observed in any cases at 10 weeks following the injury. These results revealed changes in astrocytes, microglia, oligodendrocytes in the spinal cord following transection of preganglionic axons comprising the CST, indicating their ability to respond to distal axonal injury.

Ischemia-induced increase in RGS7 mRNA expression in gerbil hippocampus.

The present study investigated the changes in the expression of regulators of G-protein-coupled signaling proteins RGS2, 7 and 8 in gerbil hippocampus to better understand alterations of G-protein-coupled receptors signaling after cerebral ischemia. In situ hybridization revealed a transient, robust early increase in RGS7 mRNA levels in the dentate gyrus after ischemia. RGS8 mRNA expression started to increase at a later time point in the CA3 region but no changes were found for RGS2. Our results show a subtype-, time-, and subregion-specific regulation in mRNA expression of RGS proteins after cerebral ischemia in gerbil hippocampus.