Dual relation between leptin and cortisol in humans is disturbed in Alzheimer's disease.
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Aged↗
Biomedical subjects
T Olsson
Publications and source records attributed to T Olsson.
[Are specialists in acute medicine needed in Sweden?].
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Clinical Competence↗
Modulation of mechanically induced calcium waves in hippocampal astroglial cells. Inhibitory effects of alpha 1-adrenergic stimulation.
The effects of different adrenoceptor agonists were investigated on mechanically induced Ca2+ waves in astroglial cells in astroglial-neuronal mixed cultures from rat hippocampus. In the initial part of the study some properties of the waves were characterized. The results show that the initiation of the Ca2+ waves was not critically dependent on extracellular Ca2+ but both the calcium signal and the propagation area of the calcium wave were significantly reduced when the experiments were performed in Ca2+-free buffer. In addition, using the phospholipase C (PLC) inhibitor U-73122 (1 microM) and the gap junction uncoupler octanol (1 mM), the results showed that the Ca2+ wave propagation required PLC activation and functional gap junctions. Further, the data also showed that the protein kinase C (PKC) activator phorbol-12-myristate-13-acetate (PMA 150 nM) reduced the spreading of the waves. The adrenoceptor agonists isoproterenol (iso; beta), phenylephrine (phe; alpha1) and clonidine (clon; alpha2) were evaluated for their short-term (<30 s) effects on the wave propagation. The propagation area was persistently decreased 1, 3 and 5 min after removal of phe. No effects were observed after incubation with iso or clon. Furthermore, using U-73122 or PMA together with phe, shortly incubated, the experiments showed that PLC was a central regulator in the initial phase of the initiation procedure of wave propagation. However, under these conditions PKC was shown not to be involved. Instead it appeared that PKC exerted its inhibitory action on the Ca2+ waves in a latter phase, after prolonged phe exposure. Taken together, the results show that the propagation of Ca2+ waves between astroglial cells in primary cultures can be inhibited/regulated in two principally different ways which involve a pronounced time component. The results also further point out the adrenergic signaling system as an important mediator of dynamic neuron-astroglial information exchange.
1-Octanol↗
Vaccination with DNA encoding an immunodominant myelin basic protein peptide targeted to Fc of immunoglobulin G suppresses experimental autoimmune encephalomyelitis.
We explore here if vaccination with DNA encoding an autoantigenic peptide can suppress autoimmune disease. For this purpose we used experimental autoimmune encephalomyelitis (EAE), which is an autoaggressive disease in the central nervous system and an animal model for multiple sclerosis. Lewis rats were vaccinated with DNA encoding an encephalitogenic T cell epitope, guinea pig myelin basic protein peptide 68-85 (MBP68-85), before induction of EAE with MBP68-85 in complete Freund's adjuvant. Compared to vaccination with a control DNA construct, the vaccination suppressed clinical and histopathological signs of EAE, and reduced the interferon gamma production after challenge with MBP68-85. Targeting of the gene product to Fc of IgG was essential for this effect. There were no signs of a Th2 cytokine bias. Our data suggest that DNA vaccines encoding autoantigenic peptides may be useful tools in controlling autoimmune disease.
Animals↗
Histochemical detection of 4-hydroxynonenal protein in Alzheimer amyloid.
The presence of lipid peroxidation product in amyloid deposits from seven patients with Alzheimer disease and nine with non-Alzheimer disease was examined immunohistochemically by means of an affinity purified anti-HNE antibody to hydroxynonenal (HNE), a marker of lipid peroxidation. A positive reaction was found in amyloid deposits in all the specimens examined: most of the perivascular areas (89%) where amyloid deposition was confirmed by Congo red staining, showed immunoreactivity with the antibody in the specimens of Alzheimer disease. Twenty-one percent of senile plaques which were also stained by Congo red staining reacted with this antibody. Several perivascular cells were also stained by anti-HNE antibody. In other neurons both in Alzheimer and non-Alzheimer disease patients, only a few percent reacted with this antibody and no statistical difference was observed between them. These results verify that lipid peroxidation via free radical injury occurs in amyloid deposits in Alzheimer amyloid. Since HNE has been identified as a cytotoxic metabolite of free radical injury, amyloid deposits in the tissue may exhibit a toxic effect during the generation process of HNE.
Aged↗
Discontinuation of treatment with IFN-beta leads to exacerbation of experimental autoimmune encephalomyelitis in Lewis rats. Rapid reversal of the antiproliferative activity of IFN-beta and excessive expansion of autoreactive T cells as disease promoting mechanisms.
IFN-beta has recently been shown to exert remarkable beneficial effects on disease development in patients with early stage relapsing-remitting MS. The specific immune mechanism(s) by which IFN-beta ameliorates this human demyelinating disease is at present undefined. One potential mechanism may reside in the antiproliferative activity of IFN-beta which may inhibit the expansion of autoaggressive T cells thereby limiting disease progression. In the present study we investigated whether the administration of recombinant rat IFN-beta (rrIFN-beta) to Lewis rats with actively induced experimental autoimmune encephalomyelitis (EAE) inhibits the expansion of encephalitogenic T cells in lymphoid organs and as such may contribute to suppression of disease activity in this widely used animal model for MS. Our data show that daily administrations of > or = 3 x 10(5) u rrIFN-beta to EAE rats, starting two days before MBP sensitization and continued for 10 days led to a dramatic and dose-dependent reduction in encephalitogenic T cells in both spleen and inguinal lymph nodes at day 8 post-immunization (p.i.). However, the rrIFN-beta-mediated reduction in effector T cells did not ameliorate paralytic disease as expected but significantly enhanced the severity of EAE. Analyses of lymphoid organs in the remission phase of EAE revealed strongly elevated numbers of encephalitogenic T cells in rrIFN-beta-treated versus control rats suggesting a rapid reversal of the antiproliferative action of rrIFN-beta followed by an overshoot in the subsequent expansion of these effector T cells. In conformity with higher numbers of encephalitogenic T cells and worsening of disease, animals also showed significantly greater perivascular inflammation in the CNS. The relevance of our findings in relation to the beneficial effects of IFN-beta in MS is discussed.
Adjuvants, Immunologic↗
Adrenal responsivity in normal aging and mild to moderate Alzheimer's disease.
BACKGROUND: Enhanced levels of cortisol have been found in moderate to severe Alzheimer's disease (AD) and in major depression, while recent studies have suggested decreased levels of serum dehydroepiandrosterone sulfate (DHAS) in patients with dementia. In this study the responsivity of the adrenal cortex to stimulation with a new low dose adrenocorticotropin (ACTH) test was investigated in patients with AD and in normal aging. METHODS: Thirteen patients with mild to moderate AD, 12 healthy old controls, and 15 young controls (78.0 +/- 8.4, 76.7 +/- 7.0, and 28.3 +/- 4.1 years old, mean: +/- SD, respectively) received an intravenous bolus injection of 1 microgram ACTH. Serum cortisol and androgen levels were analyzed before and 5, 10, 20, 25, 30, 35, 40, 60, 90, 120, 180, and 240 minutes after injection. RESULTS: The cortisol responsivity did not differ between the three groups. An enhanced release of androgens was present in patients with AD. AD per se had an independent influence on androstenedione levels after ACTH stimulation after adjustments for age and gender in a general linear regression model. CONCLUSIONS: In contrast to major depression, increased cortisol release to ACTH stimulation does not seem to be a feature of AD. Abnormal androgen levels after ACTH stimulation are characteristic features of mild to moderate Alzheimer's disease.
Adrenal Cortex Hormones↗
Molecular and genetic requirements for preferential recruitment of TCRBV8S2+ T cells in Lewis rat experimental autoimmune encephalomyelitis.
The underlying mechanisms behind the preferential expression of select TCRBV products in certain autoimmune illnesses, such as multiple sclerosis and some models of experimental autoimmune encephalomyelitis (EAE), have principally remained enigmatic. In this study, we examined the mutual role of nonself- vs self-origin of antigenic myelin basic protein (MBP) peptides and given MHC haplotypes in relation to the relative frequency of activated TCRBV8S2+ T lymphocytes in the Lewis (LEW) rat EAE model. Inbred MHC (RT1) congenic LEW rats (LEW (RT1l), LEW.1AV1 (RT1av1), and LEW.1W (RT1u)) were immunized with the 63 to 88 peptide of the guinea pig MBP (MBPGP63-88). Additionally, LEW rats were immunized with the corresponding autologous rat sequence (MBPRAT63-88). Although EAE ensued in all MBP peptide/LEW rat strain combinations, only LEW rats immunized with the heterologous MBPGP63-88 peptide elicited T cell responses encompassing a bias toward TCRBV8S2 expression, as determined by flow cytometric analyses. Reduction of TCRBV8S2+ T cells led to mitigation of disease severity in LEW rats immunized with MBPGP63-88, but not with MBPRAT63-88, indicating that critical encephalitogenic characteristics are associated with this T cell subset. We conclude that the preferential recruitment of TCRBV8S2+ T cells in the LEW rat EAE model is due to selective, high-avidity recognition of the nonself-MBPGP63-88 in the context of the RT1.Bl molecule. This inference lends support to the notion that the highly restricted TCR repertoire of the self-MBP-reactive T cells in certain genetically predisposed multiple sclerosis patients may have its source in a multistep molecular mimicry event.
Amino Acid Sequence↗
Quantitative trait loci disposing for both experimental arthritis and encephalomyelitis in the DA rat; impact on severity of myelin oligodendrocyte glycoprotein-induced experimental autoimmune encephalomyelitis and antibody isotype pattern.
Quantitative trait loci (QTL) controlling inflammatory diseases with different organ specificity may hypothetically either be unique for one disease or shared among different diseases. We have investigated whether five non-MHC QTL controlling susceptibility to experimental arthritis in the DA rat also influence myelin oligodendrocyte glycoprotein (MOG)-induced experimental autoimmune encephalomyelitis (EAE) in an F2 intercross between inbred DA and PVG.RT1a rats. Two of the five chromosome regions affecting arthritis in the DA rat also regulate phenotypes of EAE. The DA allele at markers in Cia3 (collagen-induced arthritis QTL) on chromosome 4 is associated with more severe EAE and high levels of anti-MOG antibodies of the IgG2c subclass. Since production of antibodies of the IgG2c subclass may be stimulated by Th1 cells, and there is previous evidence that such cells promote EAE, it is possible that both of the studied phenotypes are controlled by the same gene or genes regulating Th1/Th2 cell differentiation. Furthermore, we show that Oia2 (oil-induced arthritis QTL) on chromosome 4 regulates levels of anti-MOG antibodies of the IgG1 subclass and of anti-MOG IgE, but that this gene region does not affect clinical disease severity in our study. Since production of IgE and IgG1 may be stimulated by Th2 cells, this QTL may also control Th1/Th2 bias. We conclude that Cia3 and Oia2 regulate MOG-induced EAE in rats. Furthermore, since both EAE and arthritis phenotypes co-localize to these gene regions, they may harbor genes which are key regulators of pathogenic immune responses.
Animals↗
Increased reactivity to myelin oligodendrocyte glycoprotein peptides and epitope mapping in HLA DR2(15)+ multiple sclerosis.
Multiple sclerosis (MS) is a central nervous system-specific inflammatory and demyelinating disease where a myelin-directed autoimmune response is thought to be pathogenetically relevant. Myelin oligodendrocyte glycoprotein (MOG) is a surface-exposed minor myelin component that is a prime candidate autoantigen. We have investigated peripheral blood lymphocyte responses to synthetic 15-26 amino acids long overlapping MOG peptides in 20 MS patients and 14 healthy controls with the MS-associated HLA haplotype DR2(15). There were significantly increased responses, in terms of numbers of cells secreting IFN-gamma detected by Elispot in response to several MOG-derived peptides in the MS patients, but not the healthy controls. MOG peptide 63-87 evoked the strongest response, and the stimulatory property of this peptide was confirmed in additional DR2(15)+ MS patients where a peptide concentration-dependent proliferative response, which was inhibited by the addition of anti-HLA class II antibodies, was observed. This is the first work detailing putative immunodominant T cell epitopes of MOG in DR2(15)+ MS patients.
Adult↗
Central nervous system nitric oxide formation in cerebral systemic lupus erythematosus.
Systemic lupus erythematosus (SLE) is an inflammatory disease in which up to two thirds of the patients present neurological symptoms. The diagnosis of the disease is based on clinical findings and the presence of autoantibodies, and the pathogenesis is unclear. The purpose of this study was to determine if the pathogenesis was partly mediated via nitric oxide (NO) formation. Cerebrospinal fluid (CSF) samples from 15 patients with cerebral SLE were analyzed for the NO metabolites nitrite and nitrate using capillary electrophoresis. The severity of neurological symptoms was scored by dividing the patients into two groups with either mild or moderate/severe CNS involvement. All patients with cerebral SLE showed increased levels of NO metabolites. In CSF, there was a relationship between signs of NO production and clinical results showing that increased levels of nitrite and nitrate were associated with more severe neurological symptoms. These findings may shed new light on the pathogenesis of cerebral SLE, and analysis of nitrate and nitrate may prove to be of value in monitoring the activity of the disease.
Brain Diseases↗
Expression of MHC class I and beta2-microglobulin in rat spinal motoneurons: regulatory influences by IFN-gamma and axotomy.
The low expression of MHC antigens is believed to be one factor of importance contributing to the immune-privileged status of CNS neurons. We here describe that motoneurons, in contrast to other nerve cells in the lumbar spinal cord of the adult rat, express both MHC class I and beta2-microglobulin mRNA. The motoneurons also display in situ hybridization signal for IFN-gamma receptor mRNA. After a peripheral axotomy, the motoneurons show a clear upregulation of beta2-microglobulin mRNA. IFN-gamma treatment of cultured rat embryonic spinal motoneurons causes a similar upregulation of especially beta2-microglobulin. Based on these facts, we propose that spinal motoneurons can be influenced by IFN-gamma and recognized by cytotoxic CD8+ T-cells. These findings could be of relevance in the search for pathogenetic mechanisms in motoneuron-specific diseases, such as ALS.
Animals↗
Clomipramine and imipramine suppress clinical signs and T and B cell response to myelin proteins in experimental autoimmune neuritis in Lewis rats.
5-Hydroxytryptamine (5-HT) reuptake inhibitors of the zimeldine-type have induced polyneuropathies similar to Guillain-Barré syndrome (GBS) in patients with endogenous depression. Some monoamine neurotransmitters have been shown to affect immune reactions in vivo and in vitro in a concentration-dependent manner. We therefore studied the effect of the monoamine reuptake inhibitory anti-depressants, clomipramine and imipramine on specific immune response and the clinical course of experimental autoimmune neuritis (EAN), the animal model of GBS in humans. Clomipramine and imipramine both suppressed clinical signs of EAN induced by immunization with bovine peripheral nerve myelin (BPM), when given at a dose of 20 mg/kg/day intraperitoneally, via osmotic pumps. Clomipramine and imipramine reduced the numbers of Th1 cells secreting IFN-gamma in response to the neuritogenic myelin proteins BPM, P0 and P2 among lymph node mononuclear cells (MNC) from rats with EAN. The levels of cells secreting IgG antibodies to BPM, P2 and GM1 in lymph nodes were reduced at the height of EAN in clomipramine and imipramine treated animals. The action of clomipramine and imipramine on induced IFN-gamma and anti-myelin antibodies suggests that the mechanism for the suppressive effect of those substances on EAN symptoms may be due to an action on myelin T and B cell autoreactivity. Considering that the main common pharmacological principle of clomipramine and imipramine is to increase the functional activity of the nor-adrenaline (NA) and serotonin (5-HT) of the monoamines, it seems justified to postulate that the actions of clomipramine and imipramine demonstrated in this study to some extent involve NA and/or 5-HT. The immunomodulatory effects of clomipramine and imipramine call for further research on the potential role of drugs acting on the monoamine system in the treatment of autoimmune diseases, and for further studies of immunological mechanisms in the pathogenesis of depressive disorders.
Adrenergic Uptake Inhibitors↗
Fractures after stroke.
Fractures are a serious complication after stroke. Among patients with femoral neck fractures, a large subgroup have had a previous stroke. This study aimed to investigate the incidence of fractures after stroke. Included in the study were 1139 patients consecutively admitted for acute stroke. Fractures occurring from stroke onset until the end of the study or death were registered retrospectively. Hip fracture incidence was compared with corresponding rates from the general population. Patients were followed up for a total of 4132 patient-years (median 2.9 years). There were 154 fractures in 120 patients and median time between the onset of stroke and the first fracture was 24 months. Women had significantly more fractures than men (chi 2 = 15.6; p < 0.001). In patients with paresis most of the fractures affected the paretic side (chi 2 = 22.5; p < 0.001) and 84% of the fractures were caused by falls. Hip fracture was the most frequent fracture and the incidence was 2-4 times higher in stroke patients compared with the reference population. Fractures are thus a common complication after stroke. They are usually caused by falls and affect the paretic side. It is necessary to focus on the prevention of post-stroke fractures, including the prevention of both falls and osteoporosis.
Accidental Falls↗
Environmental enrichment selectively increases 5-HT1A receptor mRNA expression and binding in the rat hippocampus.
Environmental enrichment augments neuronal plasticity and cognitive function and possible mediators of these changes are of considerable interest. In this study, male rats were exposed to environmental enrichment or single housing for 30 days. Rats from the enriched group had significantly higher 5-HT1A receptor mRNA expression in the dorsal hippocampus (62%, 59% and 44% increase in the CA1, CA2 and CA3 subfields, respectively). This was associated with significantly higher [3H]8-OH-DPAT binding in the inferior part of CA1. No changes were seen for 5-HT2A or 5-HT2C receptor mRNAs. The neuronal plasticity detected after environmental change may be mediated, in part, through 5-HT1A receptors.
8-Hydroxy-2-(di-n-propylamino)tetralin↗
Regulation of telomere length by checkpoint genes in Schizosaccharomyces pombe.
We have studied telomere length in Schizosaccharomyces pombe strains carrying mutations affecting cell cycle checkpoints, DNA repair, and regulation of the Cdc2 protein kinase. Telomere shortening was found in rad1, rad3, rad17, and rad26 mutants. Telomere lengths in previously characterized rad1 mutants paralleled the replication checkpoint proficiency of those mutants. In contrast, rad9, chk1, hus1, and cds1 mutants had intact telomeres. No difference in telomere length was seen in mutants affected in the regulation of Cdc2, whereas some of the DNA repair mutants examined had slightly longer telomeres than did the wild type. Overexpression of the rad1(+) gene caused telomeres to elongate slightly. The kinetics of telomere shortening was monitored by following telomere length after disruption of the rad1(+) gene; the rate was approximately 1 nucleotide per generation. Wild-type telomere length could be restored by reintroduction of the wild-type rad1(+) gene. Expression of the Saccharomyces cerevisiae RCK1 protein kinase gene, which suppresses the radiation and hydroxyurea sensitivity of Sz. pombe checkpoint mutants, was able to attenuate telomere shortening in rad1 mutant cells and to increase telomere length in a wild-type background. The functional effects of telomere shortening in rad1 mutants were assayed by measuring loss of a linear and a circular minichromosome. A minor increase in loss rate was seen with the linear minichromosome, and an even smaller difference compared with wild-type was detected with the circular plasmid.
CDC2 Protein Kinase↗
Genetic influence on disease course and cytokine response in relapsing experimental allergic encephalomyelitis.
A protracted and relapsing form of experimental allergic encephalomyelitis (EAE) develops in the DA rat after immunization with rat spinal cord homogenate (SCH) emulsified in incomplete Freund's adjuvant (IFA). The genetic influence on this model has been analyzed by immunizing MHC congenic strains on both LEW and DA genetic backgrounds, and recombinant inbred strains between DA and E3 rats. An in situ hybridization assay was used to examine the expression of mRNA for IFN-gamma, IL-4, IL-10 and transforming growth factor (TGF)-beta both in sections of spinal cords and the antigen-induced expression for these cytokines by splenocytes after in vitro stimulation with encephalitogenic MBP peptides. The susceptibility of relapsing EAE after immunization with SCH in IFA in the DA strain, but not the E3 strain, was correlated with a lack of expression for TGF-beta in the spinal cord. The recombinant inbred DXEB rats developed a severe EAE while surprisingly no signs of disease were observed in the DXEA strain, which shares the MHC region with the DXEB strain, after immunization with the MBP 63-87 peptide. Resistance to relapsing EAE in the DXEA strain correlated with increased non-MHC controlled expression for TGF-beta and lack of IFN-gamma in the spinal cord. The same pattern of cytokine expression was seen in splenocytes after stimulation in vitro with the MBP 63-87 peptide. A spreading of the immune response to the MBP 87-110 peptide was seen. Non-MHC genes controlled the quality of this response: splenocytes from MBP 63-87 immunized DXEB rats responded in vitro towards the MBP 87-110 peptide by expressing mRNA for IFN-gamma, IL-10 and IL-4, whereas in the DXEA strain the corresponding response involved IL-4 and TGF-beta. Taken together these data show that non-MHC controlled expression of mRNA for TGF-beta is associated with resistance to EAE.
Amino Acid Sequence↗
Autoimmunity to myelin oligodendrocyte glycoprotein in rats mimics the spectrum of multiple sclerosis pathology.
Multiple sclerosis is a chronic inflammatory disease characterized by perivenous inflammation and focal destruction of myelin. Many attempts have been undertaken previously to create animal models of chronic inflammatory demyelinating diseases through autoimmunity or virus infection. Recently, however, a new model of myelin oligodendrocyte glycoprotein (MOG) induced autoimmune encephalomyelitis became available, which, in a very standardized and predictable way, leads to chronic (relapsing or progressive) disease and widespread CNS demyelination. In the present study we actively induced MOG-experimental autoimmune encephalomyelitis (EAE) in different inbred rat strains using different immunization protocols. The pathology found in our models closely reflects the spectrum of multiple sclerosis (MS) pathology: Classical MS as well as variants such as optic neuritis, Devic's disease and Marburg's type of acute MS are mimicked in rats immunized with MOG antigen. Furthermore we demonstrate, that by using the proper strain/sensitization regime, subforms of MS such as for instance neuromyelitis optica can be reproducibly induced. Our study further supports the notion, that incidence and expression of the disease in this model, alike the situation in multiple sclerosis, is determined by genetic and environmental factors.
Animals↗