Serum Levels of PCSK9 Are Increased in Patients With Active Ulcerative Colitis Representing a Potential Biomarker of Disease Activity: A Cross-sectional Study.

BACKGROUND/GOAL: Ulcerative colitis (UC) is characterized by chronic inflammation and progressive course, with potential extraintestinal complications including cardiovascular mortality. Serum proprotein convertase subtilisin/kexin type 9 (PCSK9) levels have been recently recognized as biomarkers of low-grade inflammation and cardiovascular disease. The aim of our study was to evaluate PCSK9 levels in patients with UC and different degrees of disease activity. METHODS: We prospectively recruited consecutive patients with UC attending our center at the University Hospital of Padua. Demographics, clinical characteristics, and biochemical data, including PCSK9, high sensitivity C-reactive protein, and fecal calprotectin, were recorded. Moreover, endoscopic procedures were performed in all subjects. RESULTS: We included 112 patients with UC (mean age=52.62±12.84 y; 52.62% males). Patients with UC and abnormal fecal calprotectin (≥250 µg/g) and/or C-reactive protein (≥3 mg/L) had greater levels of PCSK9 compared with UC patients with normal fecal calprotectin and high sensitivity C-reactive protein ( P =0.03 and 0.005, respectively). Higher endoscopic scores in UC were characterized by greater levels of PCSK9 ( P =0.03). Furthermore, we found a positive correlation between PCSK9 levels and fecal calprotectin ( r =0.18, P =0.04), endoscopic Mayo Score ( r =0.25, P =0.007), and UC-Riley Index ( r =0.22, P =0.01). We also found a positive correlation between PCSK9 levels and both total and low-density lipoprotein cholesterol values ( P <0.05). CONCLUSIONS: Serum PCSK9 levels are increased in patients with biochemical and endoscopic evidence of active disease in UC. Further longitudinal studies are necessary to evaluate the role of PCSK9 as a potential biomarker of disease activity and cardiovascular risk in UC.

Ligand engagement of Toll-like receptors regulates their expression in cortical microglia and astrocytes.

BACKGROUND: Toll-like receptor (TLR) activation on microglia and astrocytes are key elements in neuroinflammation which accompanies a number of neurological disorders. While TLR activation on glia is well-established to up-regulate pro-inflammatory mediator expression, much less is known about how ligand engagement of one TLR may affect expression of other TLRs on microglia and astrocytes. METHODS: In the present study, we evaluated the effects of agonists for TLR2 (zymosan), TLR3 (polyinosinic-polycytidylic acid (poly(I:C)), a synthetic analogue of double-stranded RNA) and TLR4 (lipopolysaccaride (LPS)) in influencing expression of their cognate receptor as well as that of the other TLRs in cultures of rat cortical purified microglia (>99.5 %) and nominally microglia-free astrocytes. Elimination of residual microglia (a common contaminant of astrocyte cultures) was achieved by incubation with the lysosomotropic agent L-leucyl-L-leucine methyl ester (L-LME). RESULTS: Flow cytometric analysis confirmed the purity (essentially 100 %) of the obtained microglia, and up to 5 % microglia contamination of astrocytes. L-LME treatment effectively removed microglia from the latter (real-time polymerase chain reaction). The three TLR ligands robustly up-regulated gene expression for pro-inflammatory markers (interleukin-1 and interleukin-6, tumor necrosis factor) in microglia and enriched, but not purified, astrocytes, confirming cellular functionality. LPS, zymosan and poly(I:C) all down-regulated TLR4 messenger RNA (mRNA) and up-regulated TLR2 mRNA at 6 and 24 h. In spite of their inability to elaborate pro-inflammatory mediator output, the nominally microglia-free astrocytes (>99 % purity) also showed similar behaviours to those of microglia, as well as changes in TLR3 gene expression. LPS interaction with TLR4 activates downstream mitogen-activated protein kinase and nuclear factor-κB signalling pathways and subsequently causes inflammatory mediator production. The effects of LPS on TLR2 mRNA in both cell populations were antagonized by a nuclear factor-κB inhibitor. CONCLUSIONS: TLR2 and TLR4 activation in particular, in concert with microglia and astrocytes, comprise key elements in the initiation and maintenance of neuropathic pain. The finding that both homologous (zymosan) and heterologous (LPS, poly(I:C)) TLR ligands are capable of regulating TLR2 gene expression, in particular, may have important implications in understanding the relative contributions of different TLRs in neurological disorders associated with neuroinflammation.

Molecular Epidemiology in 591 Italian Probands With Nonsyndromic Retinitis Pigmentosa and Usher Syndrome.

Purpose: To describe the molecular epidemiology of nonsyndromic retinitis pigmentosa (RP) and Usher syndrome (US) in Italian patients. Methods: A total of 591 probands (315 with family history and 276 sporadics) were analyzed. For 155 of them, we performed a family segregation study, considering a total of 382 relatives. Probands were analyzed by a customized multigene panel approach. Sanger sequencing was used to validate all genetic variants and to perform family segregation studies. Copy number variants of selected genes were analyzed by multiplex ligation-dependent probe amplification. Four patients who tested negative to targeted next-generation sequencing analysis underwent clinical exome sequencing. Results: The mean diagnostic yield of molecular testing among patients with a family history of retinal disorders was 55.2% while the diagnostic yield including sporadic cases was 37.4%. We found 468 potentially pathogenic variants, 147 of which were unpublished, in 308 probands and 66 relatives. Mean ages of onset of the different classes of RP were autosomal dominant RP, 19.3 ± 12.6 years; autosomal recessive RP, 23.2 ± 16.6 years; X-linked RP, 13.9 ± 9.9 years; and Usher syndrome, 18.9 ± 9.5 years. We reported potential new genotype-phenotype correlations in three probands, two revealed by TruSight One testing. All three probands showed isolated RP caused by biallelic variants in genes usually associated with syndromes such as PERCHING and Senior-Loken or with retinal dystrophy, iris coloboma, and comedogenic acne syndrome. Conclusions: This is the largest molecular study of Italian patients with RP in the literature, thus reflecting the epidemiology of the disease in Italy with reasonable accuracy.

Effectiveness of Third-Class Biologic Treatment in Crohn's Disease: A Multi-Center Retrospective Cohort Study.

BACKGROUND: Multiple studies have described the effectiveness of ustekinumab (UST) and vedolizumab (VDZ) in patients with Crohn's disease (CD) failing anti- Tumor necrosis factors (TNFs); however, the effectiveness of VDZ or UST as a third-class biologic has not yet been described. AIMS AND METHODS: In this retrospective multicenter cohort study, we aimed to investigate the effectiveness of VDZ and UST as a third-class biologic in patients with CD. RESULTS: Two-hundred and four patients were included; 156/204 (76%) patients received VDZ as a second- and UST as a third-class therapy (group A); the remaining 48/204 (24%) patients received UST as a second- and VDZ as a third-class therapy (group B). At week 16-22, 87/156 (55.5%) patients and 27/48 (56.2%) in groups A and B, respectively, responded to treatment (p = 0.9); 41/156 (26.2%) and 15/48 (31.2%) were in clinical remission (p = 0.5). At week 52; 89/103 (86%) patients and 25/29 (86.2%) of the patients with available data had responded to third-class treatment in groups A and B, respectively (p = 0.9); 31/103 (30%) and 47/29 (24.1%) were in clinical remission (p = 0.5). CONCLUSION: Third-class biological therapy was effective in more than half of the patients with CD. No differences in effectiveness were detected between the use of VDZ and UST as a third-class agent.

Good efficacy and safety of vedolizumab in Crohn's disease and ulcerative colitis in a real-world scenario.

BACKGROUND: Data on vedolizumab (VDZ) use in inflammatory bowel disease (IBD) patients are still limited. We aimed to assess the effectiveness and tolerability of VDZ in a real-life clinical scenario. METHODS: We retrospectively collected data of all consecutive IBD patients who started VDZ from September 2016 to December 2018 at our IBD Unit of the University Hospital of Padua and strictly followed them for 1 year. Clinical benefit (rate of clinical steroid-free remission plus clinical response), endoscopic and histological responses were evaluated over 1 year. RESULTS: A total of 117 patients who started VDZ for Crohn's disease (CD) and ulcerative colitis (UC) were included in the main analysis (69 CD patients, 48 UC patients). We obtained a clinical benefit in 68.1%, 68.1% and 59.4% of CD patients and in 68.7%, 54.2% and 54.1% of UC patients after induction, and at 30 weeks and 52 weeks, respectively. After 1 year, endoscopy response was observed in 47% of CD and 38.2% of UC patients, while the histological response was 19.6% and 23.5%, respectively. Finally, we found that 20.5% of patients needed treatment optimization, with 33.3% of them failing to respond despite this action. No deaths or serious adverse events requiring hospitalization were observed. The main cause of VDZ interruption was drug inefficacy. During the study, two patients developed new spondylarthritis, and two had a worsening of pre-existing arthralgia. CONCLUSION: Vedolizumab resulted in being effective and safe in CD as well as in UC patients.

Factors associated with disability in patients with ulcerative colitis: A cross-sectional study.

OBJECTIVES: Ulcerative colitis (UC) can give rise to several restrictions of patients' working and social activities. We aimed to determine the association between disease chronicity and the state of disability in a large population with UC. METHODS: We recruited consecutive patients with UC attending the inflammatory bowel disease (IBD) unit of the Azienda Ospedaliera of Padua between July and December 2017. We collected patients' characteristics and clinical information, and all participants completed the IBD questionnaire (IBDQ) for quality of life assessment and the IBD disability index (IBD-DI) questionnaire. Using univariate logistic regression models we assessed whether the patients' characteristics and IBD-related variables were associated with an IBD-DI score ≤3.5. Statistically significant variables in the univariate analyses were then included in a multivariate regression model. Correlations between IBD-DI and all the above mentioned characteristics were investigated using the Spearman's rank correlation coefficient. RESULTS: We included 201 patients. A positive correlation was observed between IBD-DI and IBDQ (r = 0.82, P < 0.001). Multivariate regression modelling identified the following as independent factors related to disability: active disease (partial Mayo score ≥2) (odds ratio [OR] 6.54, 95% CI 3.21-13.22), the presence of extraintestinal manifestations (EIM) (OR 2.48, 95%, CI 1.11-5.54) and occasional alcohol consumption (OR 0.39, 95% CI 0.20-0.76). CONCLUSIONS: Impaired disability is mainly correlated with disease activity, the presence of EIM and no alcohol consumption. Moreover, there is a strong correlation with patients' quality of life. Therefore, in clinical practice, greater awareness of IBD-related disability is needed to better manage patients' outcomes.

Matrix Metalloproteinase 3 Predicts Therapeutic Response in Inflammatory Bowel Disease Patients Treated With Infliximab.

BACKGROUND AND AIMS: Inflammatory bowel diseases (IBDs) are treated with anti-TNF agents. Strategies to monitor response to therapy may improve clinical control of the disease and reduce economical costs. Previous evidence suggests cleavage of infliximab (IFX) by Matrix Metalloproteinase 3 (MMP3) as a mechanism leading to loss of response. Our study aimed to evaluate if MMP3 serum levels could be considered an early marker of anti-TNF nonresponse and to analyze the correlation with other biochemical markers of treatment failure such as IFX trough levels and anti-IFX antibodies, inflammatory markers, and albumin levels. METHODS: Retrospectively, 73 IBD patients who had received IFX for at least 1 year were enrolled: 35 patients were responders and 38 were nonresponders at 52 weeks. Clinical and biochemical data (Harvey-Bradshaw index [HBI], Mayo score, body mass index [BMI], C-reactive protein [CRP], fecal calprotectin and albumin levels), MMP3 serum levels, and drug monitoring were assessed at baseline, postinduction, and 52 weeks. RESULTS: The MMP3 levels were similar at baseline (19.83 vs 17.92 ng/mL), but at postinduction, patients who failed to respond at 1 year had significantly higher levels than patients who responded (26.09 vs 8.68 ng/mL, P < 0.001); the difference was confirmed at week 52 (29.56 vs 11.48 ng/mL, P < 0.001). The MMP3 levels tended to be higher in patients without antidrug antibodies than in patients with antidrug antibodies at postinduction and 52 weeks. CONCLUSIONS: The MMP3 serum determination may represent an early marker of response to infliximab.

Microbiota changes induced by microencapsulated sodium butyrate in patients with inflammatory bowel disease.

BACKGROUND: Butyrate has shown anti-inflammatory and regenerative properties, providing symptomatic relief when orally supplemented in patients suffering from various colonic diseases. We investigated the effect of a colonic-delivery formulation of butyrate on the fecal microbiota of patients with inflammatory bowel diseases (IBDs). METHODS: In this double-blind, placebo-controlled, pilot study, 49 IBD patients (n = 19 Crohn's disease, CD and n = 30 ulcerative colitis, UC) were randomized to oral administration of microencapsulated-sodium-butyrate (BLM) or placebo for 2 months, in addition to conventional therapy. Eighteen healthy volunteers (HVs) were recruited to provide a healthy microbiota model of the local people. Fecal microbiota from stool samples was assessed by 16S sequencing. Clinical disease activity and quality of life (QoL) were evaluated before and after treatment. KEY RESULTS: At baseline, HVs showed a different microbiota composition compared with IBD patients. Sodium-butyrate altered the gut microbiota of IBD patients by increasing bacteria able to produce SCFA in UC patients (Lachnospiraceae spp.) and the butyrogenic colonic bacteria in CD patients (Butyricicoccus). In UC patients, QoL was positively affected by treatment. CONCLUSIONS AND INFERENCES: Sodium-butyrate supplementation increases the growth of bacteria able to produce SCFA with potentially anti-inflammatory action. The clinical impact of this finding requires further investigation.

Idiopathic pulmonary fibrosis and GERD: links and risks.

Gastroesophageal reflux disease (GERD) and idiopathic pulmonary fibrosis (IPF) are two pathological conditions often strictly related, even if a clear relationship of causality has not been demonstrated. GERD is a frequent comorbidity in IPF patients, as demonstrated using combined multichannel intraluminal impedance-pH, despite being mostly clinically silent. According to that, it has been hypothesized that microaspiration of gastric material may play a fundamental role in the fibrotic transformation of pulmonary parenchyma. In contrast, it cannot be excluded that IPF may favor GERD by increasing the negative intrathoracic pressure. Therefore, this relationship is uncertain as well as not univocal. Nevertheless, the latest international guidelines recommend the use of proton pump inhibitors (PPIs) in IPF based on several data showing that PPIs can stabilize lung function, reduce disease flares and hospitalizations. On the contrary, recent studies not only question the relevance of these results, but also associate the use of PPIs with an increased risk of lung infections and a negative prognostic outcome. The aim of this review is to analyze the possible links between GERD and IPF and their possible therapeutic implications, trying to translate this scientific evidence into useful information for clinical practice.

Esophageal mucosal innervation in functional heartburn: Closer to healthy asymptomatic subjects than to non-erosive reflux disease patients.

BACKGROUND: Mucosal innervation in non-erosive reflux disease (NERD; pathological esophageal acid exposure, normal macroscopic mucosa) is clearly distinct from that of healthy volunteers (HV) and from patients with esophagitis or Barrett's esophagus: The nerves in NERD are situated much closer to the luminal surface of the mucosa. Patients with functional heartburn (FH) have a similar symptom profile to patients with NERD and indistinguishable macroscopic appearances. However, they have physiological acid exposure and no reflux-symptom association. The aim of our study was to delineate the position of esophageal mucosal nerve fibers in patients with FH and compare it with that in NERD and HV. METHODS: Distal esophageal biopsies from patients with FH were immunohistochemically stained for CGRP. CGRP-positive nerve fibers were identified, and their position relative to the lumen was determined. These results were compared to our previously published cohort of HV and NERD. RESULTS: Eleven patients were included in the FH group with a mean age of 46 years (range 33-69); 7F:4M. Nine patients had visible nerve fibers. The location of the afferent nerve fibers in the distal esophageal mucosa (median of 22, range 10.4-28) was similar to the HV group (median 25.5) and significantly deeper than the superficial nerves seen in NERD (median 9.5). CONCLUSIONS: The mucosal innervation pattern in FH is more alike that of healthy individuals than that of NERD, with afferent nerves lying deep in the mucosa, away from the luminal surface. This supports the theory that heartburn in FH has a distinct nociceptive pathophysiology.

Factors Influencing Disability and Quality of Life during Treatment: A Cross-Sectional Study on IBD Patients.

BACKGROUND/AIM: Inflammatory bowel disease (IBD) is a chronic disorder affecting patients' quality of life and increasing their disability. The aim of our study was to evaluate clinical and pharmacological factors associated with impaired quality of life and disability in a large cohort of IBD patients during IBD treatment. METHODS: We consecutively and prospectively recruited all IBD patients referred to the IBD Unit of the "Azienda Ospedaliera" of Padua. Demographics and clinical information were collected, and all patients completed the IBD questionnaire (IBDQ) and the IBD-Disability Index (IBD-DI) questionnaire. A multivariate regression model and Spearman's rank correlation coefficient were applied for detecting IBD-related variables relevant to disability and quality of life. RESULTS: We included 435 IBD patients. Multivariate regression modelling identified active disease, anaemia, presence of extraintestinal manifestations, and Crohn subtype as independent predictors for both disability and poor quality of life. We observed a strong positive correlation between IBD-DI and IBDQ (r = 0.84, p < 0.001), while there was no association with ongoing therapy or other clinical features disease-related. CONCLUSIONS: Our study showed that disability and quality of life are both associated with active disease, anaemia, presence of extraintestinal manifestations, and Crohn phenotype while ongoing therapy seems not to be associated with disability and QoL during disease management.

Monogenic hypertension.

Hypertension is a significant public health problem. Thirty percent of cases are caused by a single genetic mutation. Hypertension is the predominant and usually the only manifestation in monogenic hypertension Monogenic hypertension may involve mineralcorticoid-dependent or -independent increase in Na+ transport. Diagnosis is based on routine physical examination, blood pressure measurement and laboratory analysis of renin, aldosterone, cortisol and potassium. Genetic testing is useful for confirming diagnosis and for differential diagnosis. Monogenic hypertension has autosomal dominant or autosomal recessive inheritance.

Indications and interpretation of esophageal function testing.

Esophageal symptoms are common, and can arise from mucosal, motor, functional, and neoplastic processes, among others. Judicious use of diagnostic testing can help define the etiology of symptoms and can direct management. Endoscopy, esophageal high-resolution manometry (HRM), ambulatory pH or pH-impedance manometry, and barium radiography are commonly used for esophageal function testing; functional lumen imaging probe is an emerging option. Recent consensus guidelines have provided direction in using test findings toward defining mechanisms of esophageal symptoms. The Chicago Classification describes hierarchical steps in diagnosing esophageal motility disorders. The Lyon Consensus characterizes conclusive evidence on esophageal testing for a diagnosis of gastroesophageal reflux disease (GERD), and establishes a motor classification of GERD. Taking these recent advances into consideration, our discussion focuses primarily on the indications, technique, equipment, and interpretation of esophageal HRM and ambulatory reflux monitoring in the evaluation of esophageal symptoms, and describes indications for alternative esophageal tests.

A safety review of proton pump inhibitors to treat acid-related digestive diseases.

INTRODUCTION: Proton pump inhibitors (PPIs) have become the first choice medical treatment of acid-related disease and, as with any pharmacological agent, they have been reported to be associated with some adverse events mainly linked to their chronic use. The most important postulated harms are represented by serum electrolyte alterations, vitamin B12 and iron deficiency, gastric tumors, enteric infections, spontaneous bacterial peritonitis, pneumonia, ischemic heart attacks, bone fractures, chronic kidney disease, dementia, and Alzheimer disease. Specific pathophysiological mechanisms have been identified for some of them and not for other manifestations. AREAS COVERED: However, studies on PPIs safety have generally important limitations because of their frequent retrospective design and other methodological drawbacks, such as patients' selection and residual confounders. EXPERT OPINION: Obviously, in the vast majority of the cases, adverse drug reactions cannot be assessed by means of randomized clinical trials due to the high costs, ethical reasons, and difficulties in performing prospective observational studies. So far, assessment of retrospective observational investigations remains the only method to evaluate adverse events with any drug in general and, although the weaknesses of these studies are evident, the awareness of the reported associations with the medications analyzed is important for physicians in order to manage adequately their individual patients.

Phenolic 1,3-diketones attenuate lipopolysaccharide-induced inflammatory response by an alternative magnesium-mediated mechanism.

BACKGROUND AND PURPOSE: Toll-like receptor 4 (TLR4) plays a key role in the induction of inflammatory responses both in peripheral organs and the CNS. Curcumin exerts anti-inflammatory functions by interfering with LPS-induced dimerization of TLR4-myeloid differentiation protein-2 (MD-2) complex and suppressing pro-inflammatory mediator release. However, the inhibitory mechanism of curcumin remains to be defined. EXPERIMENTAL APPROACH: Binding of bis-demethoxycurcumin (GG6) and its cyclized pyrazole analogue (GG9), lacking the 1,3-dicarbonyl function, to TLR4-MD-2 was determined using molecular docking simulations. The effects of these compounds on cytokine release and NF-κB activation were examined by ELISA and fluorescence staining in LPS-stimulated primary microglia. Interference with TLR4 dimerization was assessed by immunoprecipitation in Ba/F3 cells. KEY RESULTS: Both curcumin analogues bound to the hydrophobic region of the MD-2 pocket. However, only curcumin and GG6, both possessing the 1,3-diketone moiety, inhibited LPS-induced TLR4 dimerization, activation of NF-κB and secretion of pro-inflammatory cytokines in primary microglia. Consistent with the ability of 1,3-diketones to coordinate divalent metal ions, LPS stimulation in a low magnesium environment decreased pro-inflammatory cytokine release and NF-κB p65 nuclear translocation in microglia and decreased TLR4-MD-2 dimerization in Ba/F3 cells. Curcumin and GG6 also significantly reduced cytokine output in contrast to the pyrazole analogue GG9. CONCLUSIONS AND IMPLICATIONS: These results indicate that phenolic 1,3-diketones, with a structural motif able to coordinate magnesium ions, can modulate LPS-mediated TLR4-MD-2 signalling. Taken together, these studies identify a previously uncharacterized mechanism involving magnesium, underlying the inflammatory responses to LPS.

Systematic Review of Pharmacological Properties of the Oligodendrocyte Lineage.

Oligodendrogenesis and oligodendrocyte precursor maturation are essential processes during the course of central nervous system development, and lead to the myelination of axons. Cells of the oligodendrocyte lineage are generated in the germinal zone from migratory bipolar oligodendrocyte precursor cells (OPCs), and acquire cell surface markers as they mature and respond specifically to factors which regulate proliferation, migration, differentiation, and survival. Loss of myelin underlies a wide range of neurological disorders, some of an autoimmune nature-multiple sclerosis probably being the most prominent. Current therapies are based on the use of immunomodulatory agents which are likely to promote myelin repair (remyelination) indirectly by subverting the inflammatory response, aspects of which impair the differentiation of OPCs. Cells of the oligodendrocyte lineage express and are capable of responding to a diverse array of ligand-receptor pairs, including neurotransmitters and nuclear receptors such as γ-aminobutyric acid, glutamate, adenosine triphosphate, serotonin, acetylcholine, nitric oxide, opioids, prostaglandins, prolactin, and cannabinoids. The intent of this review is to provide the reader with a synopsis of our present state of knowledge concerning the pharmacological properties of the oligodendrocyte lineage, with particular attention to these receptor-ligand (i.e., neurotransmitters and nuclear receptor) interactions that can influence oligodendrocyte migration, proliferation, differentiation, and myelination, and an appraisal of their therapeutic potential. For example, many promising mediators work through Ca(2+) signaling, and the balance between Ca(2+) influx and efflux can determine the temporal and spatial properties of oligodendrocytes (OLs). Moreover, Ca(2+) signaling in OPCs can influence not only differentiation and myelination, but also process extension and migration, as well as cell death in mature mouse OLs. There is also evidence that oligodendroglia exhibit Ca(2+) transients in response to electrical activity of axons for activity-dependent myelination. Cholinergic antagonists, as well as endocannabinoid-related lipid-signaling molecules target OLs. An understanding of such pharmacological pathways may thus lay the foundation to allow its leverage for therapeutic benefit in diseases of demyelination.

Co-ultramicronized Palmitoylethanolamide/Luteolin Promotes the Maturation of Oligodendrocyte Precursor Cells.

Oligodendrocytes have limited ability to repair the damage to themselves or to other nerve cells, as seen in demyelinating diseases like multiple sclerosis. An important strategy may be to replace the lost oligodendrocytes and/or promote the maturation of undifferentiated oligodendrocyte precursor cells (OPCs). Recent studies show that a composite of co-ultramicronized N-palmitoylethanolamine (PEA) and luteolin (co-ultramicronized PEA/luteolin, 10:1 by mass) is efficacious in improving outcome in experimental models of spinal cord and traumatic brain injuries. Here, we examined the ability of co-ultramicronized PEA/luteolin to promote progression of OPCs into a more differentiated phenotype. OPCs derived from newborn rat cortex were placed in culture and treated the following day with 10 µM co-ultramicronized PEA/luteolin. Cells were collected 1, 4 and 8 days later and analyzed for expression of myelin basic protein (MBP). qPCR and Western blot analyses revealed a time-dependent increase in expression of both mRNA for MBP and MBP content, along with an increased expression of genes involved in lipid biogenesis. Ultramicronized PEA or luteolin, either singly or in simple combination, were ineffective. Further, co-ultramicronized PEA/luteolin promoted morphological development of OPCs and total protein content without affecting proliferation. Co-ultramicronized PEA/luteolin may represent a novel pharmacological strategy to promote OPC maturation.

Toll-like receptors 2, -3 and -4 prime microglia but not astrocytes across central nervous system regions for ATP-dependent interleukin-1ß release.

Interleukin-1ß (IL-1ß) is a crucial mediator in the pathogenesis of inflammatory diseases at the periphery and in the central nervous system (CNS). Produced as an unprocessed and inactive pro-form which accumulates intracellularly, release of the processed cytokine is strongly promoted by ATP acting at the purinergic P2X7 receptor (P2X7R) in cells primed with lipopolysaccharide (LPS), a Toll-like receptor (TLR) 4 ligand. Microglia are central to the inflammatory process and a major source of IL-1ß when activated. Here we show that purified (>99%) microglia cultured from rat cortex, spinal cord and cerebellum respond robustly to ATP-dependent IL-1ß release, upon priming with a number of TLR isoform ligands (zymosan and Pam3CSK4 for TLR2, poly(I:C) for TLR3). Cytokine release was prevented by a P2X7R antagonist and inhibitors of stress-activated protein kinases. Enriched astrocytes (≤ 5% microglia) from these CNS regions displayed responses qualitatively similar to microglia but became unresponsive upon eradication of residual microglia with the lysosomotropic agent Leu-Leu-OMe. Activation of multiple TLR isoforms in nervous system pathology, coupled with elevated extracellular ATP levels and subsequent P2X7R activation may represent an important route for microglia-derived IL-1ß. This phenomenon may have important consequences for neuroinflammation and its position to the common pathology of CNS diseases.

Hypoxia markers are expressed in interneurons exposed to recurrent seizures.

An early but transient decrease in oxygen availability occurs during experimentally induced seizures. Using pimonidazole, which probes hypoxic insults, we found that by increasing the duration of pilocarpine-induced status epilepticus (SE) from 30 to 120 min, counts of pimonidazole-immunoreactive neurons also increased (P < 0.01, 120 vs 60 and 30 min). All the animals exposed to SE were immunopositive to pimonidazole, but a different scenario emerged during epileptogenesis when a decrease in pimonidazole-immunostained cells occurred from 7 to 14 days, so that only 1 out of 4 rats presented with pimonidazole-immunopositive cells. Pimonidazole-immunoreactive cells robustly reappeared at 21 days post-SE induction when all animals (7 out of 7) had developed spontaneous recurrent seizures. Specific neuronal markers revealed that immunopositivity to pimonidazole was present in cells identified by neuropeptide Y (NPY) or somatostatin antibodies. At variance, neurons immunopositive to parvalbumin or cholecystokinin were not immunopositive to pimonidazole. Pimonidazole-immunopositive neurons expressed remarkable immunoreactivity to hypoxia-inducible factor 1α (HIF-1α). Interestingly, surgical samples obtained from pharmacoresistant patients showed neurons co-labeled by HIF-1α and NPY antibodies. These interneurons, along with parvalbumin-positive interneurons that were negative to HIF-1α, showed immunopositivity to markers of cell damage, such as high-mobility group box 1 in the cytoplasm and cleaved caspase-3 in the nucleus. These findings suggest that interneurons are continuously endangered in rodent and human epileptogenic tissue. The presence of hypoxia and cell damage markers in NPY interneurons of rats and patients presenting with recurrent seizures indicates a mechanism of selective vulnerability in a specific neuronal subpopulation.

Astrocyte-microglia cooperation in the expression of a pro-inflammatory phenotype.

Glial cells not only serve supportive and nutritive roles for neurons, but also respond to protracted stress and insults by up-regulating inflammatory processes. The complexity of studying glial activation in vivo has led to the widespread adoption of in vitro approaches, for example the use of the bacterial toxin lipopolysaccharide (LPS, a ligand for toll-like receptor 4 (TLR4)) as an experimental model of glial activation. Astrocyte cultures frequently contain minor numbers of microglia, which can complicate interpretation of responses. In the present study, enriched (≤5% microglia) astrocytes cultured from neonatal rat cortex and spinal cord were treated with the lysosomotropic agent L-leucyl-L-leucine methyl ester to eliminate residual microglia, as confirmed by loss of microglia-specific marker genes. L-Leucyl-L-leucine methyl ester treatment led to a loss of LPS responsiveness, in terms of nitric oxide and cytokine gene up-regulation and mediator (pro-inflammatory cytokines, nitric oxide) output into the culture medium. Surprisingly, when astrocyte/microglia co-cultures were then reconstituted by adding defined numbers of purified microglia to microglia-depleted astrocytes, the LPS-induced up-regulation of pro-inflammatory gene and mediator output far exceeded that observed from cultures containing the same numbers of microglia only. Similar behaviors were found when examining interleukin-1ß release caused by activation of the purinergic P2X7 receptor. Given that astrocytes greatly outnumber microglia in the central nervous system, these data suggest that a similar interaction between microglia and astrocytes in vivo may be an important element in the evolution of an inflammatory pathology.