Astrocytes in the damaged brain: Molecular and cellular insights into their reactive response and healing potential

Long considered merely a trophic and mechanical support to neurons, astrocytes have progressively taken the center stage as their ability to react to acute and chronic neurodegenerative situations became increasingly clear. Reactive astrogliosis starts when trigger molecules produced at the injury site drive astrocytes to leave their quiescent state and become activated. Distinctive morphological and biochemical features characterize this process (cell hypertrophy, upregulation of intermediate filaments, and increased cell proliferation). Moreover, reactive astrocytes migrate towards the injured area to constitute the glial scar, and release factors mediating the tissue inflammatory response and remodeling after lesion. A novel view of astrogliosis derives from the finding that subsets of reactive astrocytes can recapitulate stem cell/progenitor features after damage, fostering the concept of astroglia as a promising target for reparative therapies. But which biochemical/signaling pathways modulate astrogliosis with respect to both the time after injury and the type of damage? Are reactive astrocytes overall beneficial or detrimental for neuroprotection and tissue regeneration? This debate has been animating this research field for several years now, and an integrated view on the results obtained and the possible future perspectives is needed. With this Commentary article we have attempted to answer the above-mentioned questions by reviewing the current knowledge on the molecular mechanisms controlling and sustaining the reaction of astroglia to injury and its stem cell-like properties. Moreover, the cellular/molecular mechanisms supporting the detrimental or beneficial features of astrogliosis have been scrutinized to gain insights on possible pharmacological approaches to enhance astrocyte neuroprotective activities.     

A family based linkage analysis of HLA and 5-HTTLPR gene polymorphisms in Sardinian children with autism spectrum disorder

Autism spectrum disorders (ASD) are characterized by a broad range in clinical presentation. Although a definite genetic cause has not yet been fully demonstrated, family based studies suggest that a multigenic pattern may be responsible for susceptibility, but most results are conflicting and have yet to be replicated. The purpose of this investigation was to analyze the linkage of the human leukocyte antigen (HLA) and the human serotonin transporter coding (5-HTTLPR) genes with ASD in a group of 37 families of Sardinian ethnicity in insular Italy. In 50% of these families, ASD is linked to HLA, and in the other 50% it is linked to 5-HTTLPR polymorphic genes; in other words, linkage to one or the other was evident in all cases. Despite a very homogenous genetic pattern being generally reported for Sardinians, the linkage observed with HLA and 5-HTTLPR genetic regions indicated a statistically defined heterogeneity (p=0.002). No allelic HLA or 5-HTTLPR polymorphisms were specifically associated with ASD, suggesting these loci as markers of other genes mapped in their close proximity that may be more directly involved and thus may merit further analytical studies.     

Selective targeted delivery of TNFalpha to tumor blood vessels

We sought to enhance the selective toxicity of tumor necrosis factor alpha (TNFalpha) to permit its systemic use in cancer therapy. Because ligand-targeted therapeutics have proven successful in improving the selective toxicity of drugs, we prepared a fusion protein (L19mTNFalpha) composed of mouse TNFalpha and a high-affinity antibody fragment (L19 scFv) to the extradomain B (ED-B) domain of fibronectin, a marker of angiogenesis. L19mTNFalpha was expressed in mammalian cells, purified, and characterized. L19mTNFalpha was an immunoreactive and biologically active homotrimer. Radiolabeled L19mTNFalpha selectively targeted tumor neovasculature in tumor-bearing mice, where it accumulated selectively and persistently (tumor-to-blood ratio of the percentage of injected dose per gram [%ID/g] of 700, 48 hours from injection). L19mTNFalpha showed a greater anticancer therapeutic activity than both mTNFalpha and TN11mTNFalpha, a control fusion protein in which an antibody fragment, irrelevant in the tumor model used, substituted for L19. This activity was further dramatically enhanced by its combination with melphalan or the recently reported fusion protein L19-IL2. In conclusion, L19mTNFalpha allows concentrating therapeutically active doses of TNFalpha at the tumor level, thus opening new possibilities for the systemic use of TNFalpha in cancer therapy.     

Iron Burden and Liver Fibrosis Decrease During a Long-Term Phlebotomy Program and Iron Chelating Treatment After Bone Marrow Transplantation

In this retrospective study, we report the results of the association of a combined phlebotomy program and chelation in hereditary sideroblastic anemia (HSA) to reduce iron overload after bone marrow transplantation (BMT). A male HSA patient, not responding to pyridoxine treatment, was submitted to successful allogeneic BMT. As there was a persistence of a tissue iron overload, a regular phlebotomy program was started followed by chelation. A significant decrease of iron burden was obtained using a combined treatment with deferoxamine (DFO) and deferiprone (L1) in addition to the phlebotomy program. A 10-year follow-up shows a marked decrease in the concentration of serum ferritin, non-transferrin-bound iron (NTBI), liver iron and normal hemoglobin (Hb), which allows the patient to reach and maintain a good quality of life.     

Clonal spread of a vancomycin-resistant Enterococcus faecium strain among bloodstream-infecting isolates in Italy

Recent data indicated that the rate of vancomycin resistance in bloodstream-infecting enterococcal isolates in Italy is one of the highest in Europe. The aims of this study were to characterize bloodstream-infecting vancomycin-resistant enterococci (VRE) obtained from various Italian hospitals and to establish whether the isolates were clonally related. During the years 2001 to 2003, a total of 39 VRE isolates were obtained from 19 hospital laboratories in various areas of Italy. Species identification and resistance genotypes of the isolates were obtained by multiplex PCR. Further characterization included antibiotic susceptibility testing, pulsed-field gel electrophoresis (PFGE) of SmaI-digested genomic DNA, detection of virulence genes (esp and hyl), and multilocus sequence typing (MLST) of selected isolates. VRE were identified as 31 Enterococcus faecium (VREfm) isolates and 8 E. faecalis isolates. All but one isolate carried the vanA gene; one VREfm isolate carried the vanB gene. Analysis of the PFGE profiles showed that 28 VREfm isolates shared a similar electrophoretic profile, designed type 1, and were clonally related. All type 1 isolates were resistant to ampicillin, streptomycin, gentamicin, and rifampin and were positive for the esp gene. MLST identified an allelic profile (ST78) comprising purK allele 1, belonging to the C1 clonal lineage, characteristic of human infection and hospital outbreak isolates. The vanB-carrying VREfm isolate, of PFGE type 2, was shown to be a single-locus variant of ST78. Our data indicate that the recent increase in the number of bloodstream infections caused by VRE in Italy is due to the spread of a hospital-adapted, multidrug-resistant VREfm clone belonging to an internationally disseminated lineage.     

Serotonin transporter polymorphism modifies the association between depressive symptoms and sleep onset latency complaint in elderly people: results from the ‘InveCe.Ab’ study

Previous studies have documented the involvement of the central nervous system serotonin in promoting wakefulness. There are few and conflicting results over whether there is an actual association between bearing the short allele of serotonin transporter promoter polymorphism (5‐HTTLPR) and worse sleep quality. This study examined whether sleep onset latency complaint is associated with the 5‐HTTLPR triallelic polymorphism in the SLC6A4 gene promoter and whether this polymorphism influences the relationship between sleep onset latency complaint and depressive symptoms in elderly people. A total of 1321 community‐dwelling individuals aged 70–74 years were interviewed for sleep onset latency complaint and for sleep medication consumption. Participants’ genomic DNA was typed for 5‐HTTLPR and rs25531 polymorphisms. Depressive symptoms were evaluated with the Geriatric Depression Scale Short form and general medical comorbidity was assessed by the Cumulative Illness Rating Scale. The presence of a past history of depression was recorded. The S′ allele of the 5‐HTTLPR triallelic polymorphism was associated with sleep onset latency complaint. This association was maintained after adjusting for depressive symptoms, sex, age, history of depression and medical comorbidity. After stratification for 5‐HTTLPR/rs25531, only in S′S′ individuals high depressive symptoms were actually associated with sleep onset latency complaint. These data indicate that the low‐expressing 5‐HTTLPR triallelic polymorphism is an independent risk factor for sleep onset latency disturbance. Furthermore, the 5‐HTTLPR genotype influences the association between depressive symptoms and sleep onset latency complaint.     

Genetic Polymorphisms of Functional Candidate Genes and Recurrent Acute Otitis Media With or Without Tympanic Membrane Perforation

Evaluation of the genetic contribution to the development of recurrent acute otitis media (rAOM) remains challenging. This study aimed to evaluate the potential association between single nucleotide polymorphisms (SNPs) in selected genes and rAOM and to analyze whether genetic variations might predispose to the development of complicated recurrent cases, such as those with tympanic membrane perforation (TMP).A total of 33 candidate genes and 47 SNPs were genotyped in 200 children with rAOM (116 with a history of TMP) and in 200 healthy controls.INFγ rs 12369470CT was significantly less common in the children with rAOM than in healthy controls (odds ratio [OR] 0.5, 95% confidence interval [CI] 0.25–1, P = 0.04). Although not significant, interleukin (IL)-1β rs 1143627G and toll-like receptor (TLR)-4 rs2737191AG were less frequently detected in the children with rAOM than in controls. The opposite was true for IL-8 rs2227306CT, which was found more frequently in the children with rAOM than in healthy controls. The IL-10 rs1800896TC SNP and the IL-1α rs6746923A and AG SNPs were significantly more and less common, respectively, among children without a history of TMP than among those who suffered from this complication (OR 2.17, 95% CI 1.09–4.41, P = 0.02, and OR 0.42, 95% CI 0.21–0.84, P = 0.01).This study is the first report suggesting an association between variants in genes encoding for factors of innate or adaptive immunity and the occurrence of rAOM with or without TMP, which confirms the role of genetics in conditioning susceptibility to AOM.     

Detection of Chronic Wasting Disease in the Lymph Nodes of Free-Ranging Cervids by Real-Time Quaking-Induced Conversion

Chronic wasting disease (CWD), a transmissible spongiform encephalopathy of deer, elk, and moose, is the only prion disease affecting free-ranging animals. Since the disease was first identified in northern Colorado and southern Wyoming in 1967, new epidemic foci of the disease have been identified in 20 additional states, as well as two Canadian provinces and the Republic of South Korea. Identification of CWD-affected animals currently requires postmortem analysis of brain or lymphoid tissues using immunohistochemistry (IHC) or an enzyme-linked immunosorbent assay (ELISA), with no practical way to evaluate potential strain types or to investigate the epidemiology of existing or novel foci of disease. Using a standardized real-time (RT)-quaking-induced conversion (QuIC) assay, a seeded amplification assay employing recombinant prion protein as a conversion substrate and thioflavin T (ThT) as an amyloid-binding fluorophore, we analyzed, in a blinded manner, 1,243 retropharyngeal lymph node samples from white-tailed deer, mule deer, and moose, collected in the field from areas with current or historic CWD endemicity. RT-QuIC results were then compared with those obtained by conventional IHC and ELISA, and amplification metrics using ThT and thioflavin S were examined in relation to the clinical history of the sampled deer. The results indicate that RT-QuIC is useful for both identifying CWD-infected animals and facilitating epidemiological studies in areas in which CWD is endemic or not endemic.