Susanna Kullberg

Factors contributing to neuromuscular impairment and sarcopenia during aging.

Motor disturbances and wasting of skeletal muscles (sarcopenia) causes significant impairment of daily life activities and is a major underlying cause for hospitalization in senescence. Herein we review data and present new findings on aging-specific changes in motoneurons, skeletal muscle and the interplay between motoneurons and target muscle fibers. Although many of the changes occurring during aging may be specific to motoneurons and myofibers, respectively, evidence indicates that myofiber regeneration in sarcopenic muscle is halted at the point where reinnervation is critical for the final differentiation into mature myofibers. Combined, evidence suggests that sarcopenia to a significant extent depend on a decreased capacity among motoneurons to innervate regenerating fibers. There are also conspicuous changes in the expression of several cytokines known to play important roles in establishing and maintaining neuromuscular connectivity during development and adulthood. We also present data showing the usefulness of rodent models in studies of successful and unsuccessful patterns of aging. Finally, we show that not only dietary restriction (DR) but also activity and social environment may modulate the pattern of aging.

Microglial activation, emergence of ED1-expressing cells and clusterin upregulation in the aging rat CNS, with special reference to the spinal cord

With advancing age, the incidence of neuronal atrophy and dystrophy increases and, in parallel, behavioural sensorimotor impairment becomes overt. Activated microglia has been implicated in cytotoxic and inflammatory processes in neurodegenerative diseases as well as during aging. Here we have used immunohistochemistry and in situ hybridization to examine the expression of OX42, ED1, ED2, GFAP and clusterin in CNS of young adult and behaviourally tested aged rats (30-month-old), to study the occurrence of activated microglia/ED1 positive macrophages in senescence and to what extent this correlates with astrogliosis and signs of sensorimotor impairment among the individuals. The results show a massive region-specific increase in activated microglia and ED1 expressing cell profiles in aged rats. The infiltration was most prominent in the spinal cord dorsal columns, including their sensory relay nuclei, and the outer portions of the lateral and ventral columns. At such sites the occurrence of macrophages coincided with increased levels of GFAP and positive correlations were evident between the labeling for, on the one hand, OX42 and, on the other, GFAP and ED1. Also, the ventral and dorsal roots were heavily infiltrated by ED1 positive cells. The signs of gliosis were most pronounced among aged rats with advanced sensorimotor impairment. In contrast, the grey matter of aged rats showed very few activated microglia/ED1 labeled cells despite signs of focal astrogliosis. ED2 expression was confined to perivascular cells and leptominges with a similar labeling pattern in young and aged rats. In aged rats increased expression of clusterin was observed in GFAP-immunoreactive profiles of the white matter only. It is suggested that this increase may reflect a response to degenerative/inflammatory processes.

Regulation of neurotrophin signaling in aging sensory and motoneurons

A hallmark of senescence is sensorimotor impairment, involving locomotion and postural control as well as fine-tuned movements. Sensory and motoneurons are not lost to any significant degree with advancing age, but do show characteristic changes in gene-expression pattern, morphology, and connectivity. This review covers recent experimental findings corroborating that alterations in trophic signaling may induce several of the phenotypic changes seen in primary sensory and motoneurons during aging. Furthermore, the data suggests that target failure, and/or breakdown of neuron-target interaction, is a critical event in the aging process of sensory and motoneurons.

The lung microbiota in early rheumatoid arthritis and autoimmunity

BackgroundAirway abnormalities and lung tissue citrullination are found in both rheumatoid arthritis (RA) patients and individuals at-risk for disease development. This suggests the possibility that the lung could be a site of autoimmunity generation in RA, perhaps in response to microbiota changes. We therefore sought to test whether the RA lung microbiome contains distinct taxonomic features associated with local and/or systemic autoimmunity.Methods16S rRNA gene high-throughput sequencing was utilized to compare the bacterial community composition of bronchoalveolar lavage fluid (BAL) in patients with early, disease-modifying anti-rheumatic drugs (DMARD)-naïve RA, patients with lung sarcoidosis, and healthy control subjects. Samples were further assessed for the presence and levels of anti-citrullinated peptide antibodies (including fine specificities) in both BAL and serum.ResultsThe BAL microbiota of RA patients was significantly less diverse and abundant when compared to healthy controls, but similar to sarcoidosis patients. This distal airway dysbiosis was attributed to the reduced presence of several genus (i.e., Actynomyces and Burkhordelia) as well as reported periodontopathic taxa, including Treponema, Prevotella, and Porphyromonas. While multiple clades correlated with local and systemic levels of autoantibodies, the genus Pseudonocardia and various related OTUs were the only taxa overrepresented in RA BAL and correlated with higher disease activity and erosions.ConclusionsDistal airway dysbiosis is present in untreated early RA and similar to that detected in sarcoidosis lung inflammation. This community perturbation, which correlates with local and systemic autoimmune/inflammatory changes, may potentially drive initiation of RA in a proportion of cases.

Upregulation of GFRα‐1 and c‐ret in primary sensory neurons and spinal motoneurons of aged rats

Aging is associated with a decline in neuromuscular and somatosensory functions. Senile muscle atrophy, considered to be of neurogenic origin, is prevalent, and sensory thresholds increase with age. However, the loss of motoneurons and primary sensory neurons is small, while sensory and motor innervation appears disturbed due to aging‐related axon lesions. One mechanism which may play a role in this process is altered trophin signaling. We here report that the glial cell line‐derived neurotrophic factor (GDNF) receptor GFRα‐1 mRNA and GFRα‐1 protein‐like immunoreactivity are upregulated in spinal motoneurons, and in dorsal root ganglion neurons of 30‐month‐old rats. The established signaling mechanism for the GDNF/GFRα‐1 complex is through binding to the tyrosine kinase receptor encoded by the c‐ret proto‐oncogene, and we also show here that c‐ret mRNA is upregulated in both motoneurons and primary sensory neurons of aged rats. The findings reported here, combined with evidence presented in other studies of changes in p75NTR and trk receptor expressions in aging primary sensory neurons and motoneurons, point at marked alterations in trophin signaling in senescence. J. Neurosci. Res. 57:153–165, 1999.

Sarcoidosis incidence and prevalence: a nationwide register-based assessment in Sweden.

Our objective was to estimate the contemporary incidence and prevalence of sarcoidosis using Swedish population-based register data. Adults with any sarcoidosis-coded visit were identified from the National Patient Register (hospitalisations 1964–2013 and outpatient care 2001–2013). Demographic and medication dispensing data were retrieved from national registers. We estimated the prevalence of sarcoidosis in 2013 overall and by county of residence. The incidence of sarcoidosis during 2003–2012 was estimated by sex, age, education level and year of diagnosis. Case definitions were varied to test their robustness. More than 16 000 individuals had a history of sarcoidosis in 2013. When defined as two or more sarcoidosis-coded visits, the prevalence was 160 per 100 000. Using different definitions, the prevalence ranged from 152 (requiring a specialist visit) to 215 per 100 000 (only one visit required). The highest prevalence was observed in northern less densely populated counties. The incidence was 11.5 per 100 000 per year and varied by −10% to +30% depending on case definition. The incidence peaked in males aged 30–50 years and in females aged 50–60 years, but did not differ by education level and was stable over time. This study represents the largest epidemiological investigation of sarcoidosis using population-based individual-level data. Age at diagnosis in men was 10 years younger than in women and geographical variation was observed. Sarcoidosis occurrence varied by region, age and sex; age at onset was 10 years younger in males than in females http://ow.ly/mKyN300E4Kp

Expanded lung T-bet+RORγT+ CD4+ T-cells in sarcoidosis patients with a favourable disease phenotype.

Disease phenotypes of pulmonary sarcoidosis are distinguished by clinical rather than immunological criteria. We aimed to characterise patterns of CD4+ T-cell lineage plasticity underlying the differences in clinical presentation and disease course between the acute form, Löfgrens syndrome, and the heterogeneous, potentially progressive “non-Löfgren” form. 33 pulmonary sarcoidosis patients and nine controls underwent bronchoscopy with bronchoalveolar lavage. CD4+ T-cell transcription factor, chemokine receptor and T-cell receptor expression, proliferation and cytokine production were assessed in the lavage fluid and peripheral blood using flow cytometry and multicolour FluoroSpot. CD4+ T-cells simultaneously expressing the T-helper cell (Th)1 and Th17 transcriptional regulators T-bet and RORγT (T-bet+RORγT+) were identified in the lavage, but not blood, of all subjects, and to a significantly higher degree in Löfgrens patients. T-bet+RORγT+ cells proliferated actively, produced interferon (IFN)γ and interleukin (IL)-17A, co-expressed the chemokine receptors CXCR3 and CCR6, and correlated with nonchronic disease. T-cell receptor-restricted Vα2.3+Vβ22+ T-cells strongly co-expressed T-bet/RORγT and CXCR3/CCR6. Cytokine production was more heterogeneous in Löfgrens patients, with significantly higher IL-17A, IL-10, IL-22 and IL-2, but lower IFNγ. Here we demonstrate the presence of lung T-bet+RORγT+CXCR3+CCR6+ CD4+ T-cells and Th17-associated cytokines especially in sarcoidosis patients with a favourable prognosis, suggesting a Th1/Th17-permissive environment in the lung with implications for disease resolution. Lung CD4+ T-cells expressing both T-bet and RORγT are found especially in sarcoidosis patients with a good prognosis http://ow.ly/10ai8H

Increased glutathione levels in neurochemically identified fibre systems in the aged rat lumbar motor nuclei

The spinal cord motor nuclei have been the focus of a number of investigations exploring neurodegenerative mechanisms, e.g. excitotoxicity mediated by glutamate and oxidative stress. Here, high‐resolution quantitative post‐embedding immunocytochemistry with antibodies to oxidized and reduced glutathione (GSH), an ubiquitously expressed scavenger of free radicals, was used to examine if GSH synthesis is upregulated pre‐ and/or postsynaptically in the lumbar motor nuclei of aged (30 month old) rats. The purpose was, moreover, to resolve the extent of correlation between GSH expression, transmitter identity and degenerative changes. Tissue from young adult rats was co‐processed for comparison. The quantitative immunogold analysis revealed an increase in GSH‐immunoreactivity in both pre‐ and postsynaptic compartments in the lumbar motor nuclei of aged rats. Presynaptically, the enrichment of GSH‐immunoreactivity was seen in axonal boutons of normal appearance, and was furthermore restricted to the extra‐mitochondrial compartment. Postsynaptically, the aged rats disclosed, in comparison with young adults, higher values for GSH‐immunoreactivity both over mitochondria (+49%) and cytoplasmic matrix (+130%). When analysing the transmitter identity of the bouton profiles, it turned out that close to 50% of all glutamate‐immunoreactive boutons in the aged rats contained very high levels (> 40 gold particles/μm2) of GSH‐immunoreactivity. Strong GSH‐immunoreactivity was also a typical feature of a subset of axon terminal‐ and axon fibre‐like profiles in the aged rat that showed signs of axon dystrophy and degeneration. When comparing with normally appearing axon fibre profiles located in close vicinity, the population of aberrant axons had higher average levels of glutamate‐immunoreactivity (+93%), and lower average levels of glycine‐immunoreactivity (–88%). No difference was seen regarding the levels of GABA. The results of this study lend support to the idea that aging in the spinal cord motor nuclei is associated with an increased oxidative stress and indicate that different transmitter systems are differentially affected by the degenerative process.

T-cell activation and HLA-regulated response to smoking in the deep airways of patients with multiple sclerosis

Cigarette smoking is a risk factor for multiple sclerosis (MS), and the risk is further multiplied for HLA-DRB1*15(+) smokers. To define the smoke-induced immune responses in the lung we performed bronchoscopy with bronchoalveolar lavage (BAL) on smokers and non-smokers, both MS-patients and healthy volunteers. In the BAL, non-smokers with MS showed an increased preformed CD40L expression in CD4(+) T-cells while smokers displayed an increase in proliferating (Ki-67(+)) T-cells. In addition, our results confirm that smoking induces an increase of alveolar macrophages in BAL, and further defined a significant attenuation of this response in carriers of the HLA-DRB1*15 allele, in both MS patients and healthy controls. This first systematic investigation of the immune response in the lungs of smokers and non-smokers diagnosed with MS, thus suggests an MS-associated lung T-cell phenotype, involvement of a specific T-cell response to smoke, and a genetic regulation of the macrophage response.

Expression Profile of Six RNA-Binding Proteins in Pulmonary Sarcoidosis

Background Sarcoidosis is characterised by up-regulation of cytokines and chemokine ligands/receptors and proteolytic enzymes. This pro-inflammatory profile is regulated post-transcriptionally by RNA-binding proteins (RBPs). We investigated in vivo expression of six RBPs (AUF1, HuR, NCL, TIA, TIAR, PCBP2) and two inhibitors of proteolytic enzymes (RECK, PTEN) in pulmonary sarcoidosis and compared it to the expression in four control groups of healthy individuals and patients with other respiratory diseases: chronic obstructive pulmonary disease (COPD), asthma and idiopathic interstitial pneumonias (IIPs). Methods RT-PCR was used to quantify the mRNAs in bronchoalveolar (BA) cells obtained from 50 sarcoidosis patients, 23 healthy controls, 30 COPD, 19 asthmatic and 19 IIPs patients. Flow cytometry was used to assess intracellular protein expression of AUF1 and HuR in peripheral blood T lymphocytes (PBTLs) obtained from 9 sarcoidosis patients and 6 healthy controls. Results Taking the stringent conditions for multiple comparisons into consideration, we consistently observed in the primary analysis including all patients regardless of smoking status as well as in the subsequent sub-analysis limited for never smokers that the BA mRNA expression of AUF1 (p<0.001), TIA (p<0.001), NCL (p<0.01) and RECK (p<0.05) was decreased in sarcoidosis compared to healthy controls. TIA mRNA was also decreased in sarcoidosis compared to both obstructive pulmonary diseases (COPD and asthma; p<0.001) but not compared to IIPs. There were several positive correlations between RECK mRNA and RBP mRNAs in BA cells. Also sarcoidosis CD3+, CD4+ and CD8+ PBTLs displayed lower mean fluorescence intensity of AUF1 (p≤0.02) and HuR (p≤0.03) proteins than control healthy PBTLs. Conclusion mRNA expressions of three RBPs (AUF1, TIA and NCL) and their potential target mRNA encoding RECK in BA cells and additionally protein expression of AUF1 and HuR in PBTLs were down-regulated in our sarcoidosis patients compared to healthy individuals. Its significance, e.g. for stability of mRNAs encoding pro-inflammatory factors, should be further explored in sarcoidosis.